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# CDS view entities
- [CDS view entities](#cds-view-entities)
- [More Information](#more-information)
- [Executable Example](#executable-example)
Core data services (CDS) are an infrastructure for defining and consuming semantically rich data models on the [standard database](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenstandard_db_glosry.htm) of an [AS ABAP](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenas_abap_glosry.htm).
CDS basically is an enhancement of ABAP SQL to reduce the rich variety of syntax.
> **💡 Note**<br>
> - For cheat sheet content on CDS views, check out [this blog](https://blogs.sap.com/2022/10/24/feature-matrix-data-modeling-with-abap-core-data-services/).
> - The executable example focuses on CDS view entities and covers a selection of features.
> - The sample CDS view entities are designed to demonstrate a selection of features with a limited number of artifacts. They are not intended to be role models for proper CDS view design. They focus on syntax options only. They are not intended to solve concrete programming tasks. You should always work out your own solution for each individual case.
## More Information
- [Feature Matrix: Data Modeling with ABAP Core Data Services](https://blogs.sap.com/2022/10/24/feature-matrix-data-modeling-with-abap-core-data-services/)
- [ABAP CDS Cheat Sheet: Amounts and Quantities in ABAP CDS](https://blogs.sap.com/2022/07/07/abap-cds-cheat-sheet-amounts-and-quantities-in-abap-cds/)
- [Section *ABAP - Core Data Services (ABAP CDS)* in the ABAP keyword Documentation](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abencds.htm)
## Executable Example
[zcl_demo_abap_cds_ve](./src/zcl_demo_abap_cds_ve.clas.abap)
The example covers the following topics:
- Operands, expressions, built-in functions, and input parameters in CDS view entities
- Selecting data from CDS view entities using ABAP SQL SELECT statements
- Joins
- Note: A sample CDS view entity contains multiple joins. You can comment in/out code sections to see the effect. See the notes in the view.
- Excursion: Joins in ABAP SQL
- Associations
- Defining views with associations
- Exposing associations
- Using exposed associations in ABAP statements
Note ...
- the comments in the example CDS view entities (zdemo_abap_cds_ve...) and the [class](./src/zcl_demo_abap_cds_ve.clas.abap).
- the steps outlined [here](README.md#-getting-started-with-the-examples) about how to import and run the code.

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|[A Glimpse on AMDP](12_AMDP.md)|Covers ABAP Managed Database Procedures (AMDP): AMDP Procedures and AMDP Functions (including CDS Table Functions)|[zcl_demo_abap_amdp](./src/zcl_demo_abap_amdp.clas.abap)| |[A Glimpse on AMDP](12_AMDP.md)|Covers ABAP Managed Database Procedures (AMDP): AMDP Procedures and AMDP Functions (including CDS Table Functions)|[zcl_demo_abap_amdp](./src/zcl_demo_abap_amdp.clas.abap)|
|[Program Flow Logic](13_Program_Flow_Logic.md)|Deals with control structures (`IF`, `CASE`), loops (`DO`, `WHILE`) and exception handling|[zcl_demo_abap_prog_flow_logic](./src/zcl_demo_abap_prog_flow_logic.clas.abap)| |[Program Flow Logic](13_Program_Flow_Logic.md)|Deals with control structures (`IF`, `CASE`), loops (`DO`, `WHILE`) and exception handling|[zcl_demo_abap_prog_flow_logic](./src/zcl_demo_abap_prog_flow_logic.clas.abap)|
|[A Glimpse on ABAP Unit Tests](14_ABAP_Unit_Tests.md)|Contains basic information about unit testing in ABAP|[zcl_demo_abap_unit_test](./src/zcl_demo_abap_unit_test.clas.abap)| |[A Glimpse on ABAP Unit Tests](14_ABAP_Unit_Tests.md)|Contains basic information about unit testing in ABAP|[zcl_demo_abap_unit_test](./src/zcl_demo_abap_unit_test.clas.abap)|
|[CDS View Entities](15_CDS_view_entities.md)|Note that cheat sheet content is available in [this blog](https://blogs.sap.com/2022/10/24/feature-matrix-data-modeling-with-abap-core-data-services/). The focus here is on the example CDS artifacts and the [executable example class](./src/zcl_demo_abap_cds_ve.clas.abap), which include comments.|[zcl_demo_abap_cds_ve](./src/zcl_demo_abap_cds_ve.clas.abap)|
<br> <br>

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***********************************************************************
*
* ABAP cheat sheet: CDS View Entities
*
* -------------------------- PURPOSE ----------------------------------
* - Example to demonstrate CDS view entities. See the CDS view entities
* that are used in the example for more details.
* - Topics covered: Operands, expressions, and built-in functions in the
* SELECT list of CDS view entities, input parameters, joins,
* associations
* - Note: In ADT, check out the CDS view entities used in this example
* by holding down CTRL and clicking on the CDS view entity. This will
* take you to the artifact. There you can choose F8 to open the data
* preview.
* ----------------------- GETTING STARTED -----------------------------
* - Open the class with the ABAP Development Tools (ADT).
* - Choose F9 to run the class.
* - Check the console output.
* - To understand the context and the ABAP syntax used, refer to the
* notes included in the class as comments or refer to the respective
* topic in the ABAP Keyword Documentation.
* - Due to the amount of console output, the examples contain numbers
* (e.g. 1) ..., 2) ..., 3) ...) for the individual example sections.
* Also, the variable name is displayed in most cases. So to find
* the relevant output in the console easier and faster, just search
* for the number/variable name in the console (CTRL+F in the console)
* or use the debugger.
*
* ----------------------------- NOTE -----------------------------------
* The code presented in this class is intended only to support the ABAP
* cheat sheets. It is not intended for direct use in a production system
* environment. The code examples in the ABAP cheat sheets are primarily
* intended to provide a better explanation and visualization of the
* syntax and semantics of ABAP statements, not to solve concrete
* programming tasks. For production application programs, you should
* always work out your own solution for each individual case. There is
* no guarantee for the correctness or completeness of the code.
* Furthermore, there is no legal responsibility or liability for any
* errors or their consequences that may occur when using the the example
* code.
*
***********************************************************************
"! <p class="shorttext synchronized">ABAP cheat sheet: CDS view entities</p>
"! Example to demonstrate CDS view entities.<br>Choose F9 in ADT to run the class.
CLASS zcl_demo_abap_cds_ve DEFINITION
PUBLIC
FINAL
CREATE PUBLIC .
PUBLIC SECTION.
INTERFACES:
if_oo_adt_classrun.
CLASS-METHODS class_constructor.
ENDCLASS.
CLASS zcl_demo_abap_cds_ve IMPLEMENTATION.
METHOD class_constructor.
"Filling demo database tables.
zcl_demo_abap_flight_tables=>fill_dbtabs( ).
"Some more database table insertions for this particular example
MODIFY zdemo_abap_carr FROM TABLE @( VALUE #(
( carrid = 'SQ'
carrname = 'Singapore Airlines'
currcode = 'SGD'
url = 'http://www.singaporeair.com ' )
( carrid = 'QF'
carrname = 'Qantas Airways'
currcode = 'AUD'
url = 'http://www.qantas.com.au' ) ) ).
MODIFY zdemo_abap_flsch FROM TABLE @( VALUE #(
( carrid = 'UA'
connid = 3517
countryfr = 'DE'
cityfrom = 'FRANKFURT'
airpfrom = 'FRA'
countryto = 'US'
cityto = 'NEW YORK'
airpto = 'JFK'
fltime = 495
deptime = '104000'
arrtime = '125500'
distance = 6162
distid = 'KM'
fltype = ''
period = 0 ) ) ).
MODIFY zdemo_abap_fli FROM TABLE @( VALUE #( ( carrid = 'UA' ) ) ).
ENDMETHOD.
METHOD if_oo_adt_classrun~main.
DATA(output) = NEW zcl_demo_abap_display( out ).
output->display( `ABAP Cheat Sheet: CDS View Entities` ).
output->display( `1) Operands, expressions and built-in functions ` &&
`in a CDS view entity` ).
"The following ABAP SQL SELECT statement uses a CDS view entity as
"the data source. All data is retrieved. The sample CDS view entity
"uses many operands, expressions and built-in functions to demonstrate
"various syntax options. In addition, the view contains an input
"parameter that must be provided with an actual parameter and
"specified in the ABAP SQL SELECT statement.
"In ADT, check out the CDS view entity by holding down CTRL and clicking
"on the CDS view entity. This will take you to the artifact. There you
"can choose F8 to open the data preview.
SELECT *
FROM zdemo_abap_cds_ve_sel( p_smax = 20 )
ORDER BY CarrierId
INTO TABLE @DATA(select_from_cds).
output->display( input = select_from_cds name = `select_from_cds` ).
**********************************************************************
output->next_section( `2) Aggregate Expressions` ).
"The following ABAP SQL SELECT statement uses a CDS view entity as
"the data source. All data is retrieved. The sample CDS view entity
"uses aggregate expressions.
SELECT *
FROM zdemo_abap_cds_ve_agg_exp
ORDER BY carrid
INTO TABLE @DATA(agg_expr).
output->display( input = agg_expr name = `agg_expr` ).
**********************************************************************
output->next_section( `3) Joins` ).
"The following ABAP SQL SELECT statement uses a CDS view entity as
"the data source. All data is retrieved. The sample CDS view entity
"contains multiple joins.
"The CDS view entity is designed to contain different join variants
"in one artifact. There, you can comment in/out code sections to
"check out the individual join variants. Therefore, the result of
"the following SELECT statement depends on which section you have
"commented in in the CDS view entity.
SELECT *
FROM zdemo_abap_cds_ve_joins
ORDER BY carrid
INTO TABLE @DATA(cds_joins).
output->display( input = cds_joins name = `cds_joins` ).
**********************************************************************
output->next_section( `4) Excursion: ABAP SQL and joins` ).
"The following ABAP SQL SELECT statements uses a CDS view entity as
"the data source. The sample CDS view entity contains multiple
"joins.
"The following ABAP SQL SELECT statements are intended to reproduce
"the different joins that are performed by the CDS view entity.
"Inner, left and right outer, and cross joins are covered. The data
"sources for the SELECT statements are the database tables.
"Note:
"- The prefix ~ is used in the ABAP SQL statements instead of . in
" the CDS view entity.
"- To demonstrate the handling of null values, some SELECT statements
"contain the coalesce function and CASE expressions similar to the
"CDS view entity.
output->display( `----- Inner join -----` ).
SELECT _carr~carrid,
_carr~carrname,
_flsch_in~cityfrom AS cityfr_in,
_flsch_in~cityto AS cityto_in
FROM zdemo_abap_carr AS _carr
INNER JOIN zdemo_abap_flsch AS _flsch_in
ON _carr~carrid = _flsch_in~carrid
ORDER BY _carr~carrid
INTO TABLE @DATA(sql_inner_join).
output->display( input = sql_inner_join name = `sql_inner_join` ).
output->display( `----- Left outer join -----` ).
SELECT _carr~carrid,
_carr~carrname,
_flsch_lo~cityfrom AS cityfr_lo,
coalesce( _flsch_lo~cityto, '???' ) AS cityto_lo
FROM zdemo_abap_carr AS _carr
LEFT OUTER JOIN zdemo_abap_flsch AS _flsch_lo
ON _carr~carrid = _flsch_lo~carrid
ORDER BY _carr~carrid
INTO TABLE @DATA(sql_left_outer_join).
output->display( input = sql_left_outer_join name = `sql_left_outer_join` ).
output->display( `----- Right outer join -----` ).
SELECT _carr~carrid,
_carr~carrname,
CASE WHEN _carr~url IS NOT NULL THEN _carr~url
ELSE '!!!'
END AS url_ro,
_flsch_ro~cityfrom AS cityfr_ro,
_flsch_ro~cityto AS cityto_ro
FROM zdemo_abap_carr AS _carr
RIGHT OUTER JOIN zdemo_abap_flsch AS _flsch_ro
ON _carr~carrid = _flsch_ro~carrid
ORDER BY _carr~carrid
INTO TABLE @DATA(sql_right_outer_join).
output->display( input = sql_right_outer_join name = `sql_right_outer_join` ).
output->display( `----- Cross join -----` ).
SELECT _carr~carrid,
_carr~carrname,
_flsch_cr~cityfrom AS cityfr_cr,
_flsch_cr~cityto AS cityto_cr
FROM zdemo_abap_carr AS _carr
CROSS JOIN zdemo_abap_flsch AS _flsch_cr
ORDER BY _carr~carrid
INTO TABLE @DATA(sql_cross_join).
output->display( input = sql_cross_join name = `sql_cross_join` ).
"Just a check what join example is currently commented in
IF cds_joins = sql_inner_join.
output->display( `In the example CDS view entity, the inner join example is commented in.` ).
ELSEIF cds_joins = sql_left_outer_join.
output->display( `In the example CDS view entity, the left outer join example is commented in.` ).
ELSEIF cds_joins = sql_right_outer_join.
output->display( `In the example CDS view entity, you have the right outer join example is commented in.` ).
ELSEIF cds_joins = sql_cross_join.
output->display( `In the example CDS view entity, you have the cross join example is commented in.` ).
ELSE.
output->display( `In the example CDS view entity, there is some other code present.` ).
ENDIF.
**********************************************************************
output->next_section( `Associations` ).
output->display( `5) Selecting data from a CDS view that contains associations` ).
"The following ABAP SQL SELECT statement uses a CDS view entity as
"the data source. All data is retrieved. The sample CDS view entity
"contains multiple associations.
"Some fields of some associations are used in the element list of the
"CDS view entity. This data is included in the result set. Some
"associations are exposed but no fields of those associations are
"included in the element list. Therefore, no join is instantiated on
"the database and no data from these exposed assocations is included
"in the result set.
SELECT *
FROM zdemo_abap_cds_ve_assoc
ORDER BY carrier
INTO TABLE @DATA(assoc).
output->display( input = assoc name = `assoc` ).
**********************************************************************
output->next_section( `Using exposed associations in ABAP SQL statements: ...` ).
"The following examples use path expressions to access the association
"targets of exposed associations.
output->display( `6) ... SELECT clause` ).
"The following ABAP SQL SELECT statement uses a CDS view entity as
"the data source. The statement uses an exposed association.
"The SELECT list contains fields from the exposed association. Only in
"this case (when a consumer, such as an ABAP SQL statement, requests
"data) is the join instantiated on the database.
"Note:
"- No attributes are specified for the path expression (attributes
" are covered in examples further down). In particular, a join type is
" not explicitly specified. In such a case, the join type depends on
" the place where the path expression is used. Since the path expression
" is used in the SELECT list of an ABAP SQL SELECT statement (where
" fields are specified), a LEFT OUTER JOIN is used by default.
"- The coalesce function is included for a field to handle null values.
SELECT carrier,
\_carr3-carrname,
coalesce( \_carr3-url, '###' ) AS cityto_lo
FROM zdemo_abap_cds_ve_assoc
ORDER BY carrier
INTO TABLE @DATA(assoc_exp_select).
output->display( input = assoc_exp_select name = `assoc_exp_select` ).
**********************************************************************
output->next_section( `7) ... FROM clause` ).
"The following ABAP SQL SELECT statement uses a CDS view entity as
"the data source. All data is retrieved.
"In this case, an exposed association is used in the FROM clause.
"Note:
"- No join type is explicitly specified. As mentioned above, the
" position of the path expression is important. In this case (when
" used in the FROM clause), an INNER JOIN is used by default.
"- You can open the data preview for the CDS view entity used and
" compare the result set with the output here. Due to the inner
" join, non-existent 'carrid' values in the association target are
" not contained in the result set.
SELECT *
FROM zdemo_abap_cds_ve_assoc\_carr3 AS _exp
ORDER BY carrid
INTO TABLE @DATA(assoc_exp_from).
output->display( input = assoc_exp_from name = `assoc_exp_from` ).
"The following ABAP SQL SELECT statement is intended to reproduce
"the data retrieval as above.
"The statement uses the same CDS view entity as data source that
"is used by the CDS view entity above as data source.
"An inner join is performed on a database table (the _carr3
"association from above has this table defined as the association
"target in the CDS view entity) since the inner join is used by
"default above so as to reproduce the effect. The result set
"should be the same as above.
SELECT _carr~mandt,
_carr~carrid,
_carr~carrname,
_carr~currcode,
_carr~url
FROM zdemo_abap_cds_ve_assoc_e AS _cds
JOIN zdemo_abap_carr AS _carr ON _cds~carrid = _carr~carrid
ORDER BY _carr~carrid
INTO TABLE @DATA(sql_repr).
output->display( input = sql_repr name = `sql_repr` ).
IF sql_repr = assoc_exp_from.
output->display( `The result sets are the same.` ).
ELSE.
output->display( `The result sets are differrent.` ).
ENDIF.
**********************************************************************
output->next_section( `8) ... Specifying attributes ` ).
"The following ABAP SQL SELECT statement uses a CDS view entity as
"the data source. The statement uses an exposed association.
"The SELECT list contains a path expression that is specified with
"an attribute.
"Note:
"- Cardinality, join types, and filter conditions can be used as
" attributes.
"- In the example, only the cardinality is specified.
"- The cardinality can be specified to prevent syntax warnings/errors
" in cases where the cardinality of the association does not match
" the way it is used in a path expression.
"- The example does not explicitly specify a join type. As mentioned
" above, if not explicitly specified, the join type depends on where
" the path expression is used. Here, a column is specified in the
" SELECT list. This means that a LEFT OUTER JOIN is used by default.
"- The result set should contain an entry for 'UA' having an initial
" value for 'fldate'.
SELECT carrid,
connid,
cityfrom,
cityto,
"Without specifying the cardinality, the following warning
"occurs: Using association "_FLI" can increase the cardinality
"of the results set
"\_fli-fldate
\_fli[ (*) ]-fldate AS flightdate
"The specification above corresponds to the following specification
"that includes an explicit specification of LEFT OUTER
"\_fli[ (*) LEFT OUTER ]-fldate
FROM zdemo_abap_cds_ve_assoc_e
ORDER BY carrid, connid, flightdate
INTO TABLE @DATA(assoc_attr_card).
output->display( input = assoc_attr_card name = `assoc_attr_card` ).
"Specifying the join type explicitly
"- INNER, LEFT/RIGHT OUTER are possible
"- The join type can only be specified together with the cardinality.
"- In the result set of the example, the 'UA' entry should not be
" contained.
SELECT carrid,
connid,
cityfrom,
cityto,
\_fli[ (*) INNER ]-fldate AS flightdate
FROM zdemo_abap_cds_ve_assoc_e
ORDER BY carrid, connid, flightdate
INTO TABLE @DATA(assoc_attr_joty).
output->display( input = assoc_attr_joty name = `assoc_attr_joty` ).
"Specifying conditions
"- Filter conditions can be specified for the current association
"- The addition WHERE is optional in cases where the filter condition
" is the only attribute specified in the square brackets.
"- When the association is instantiated as a join, the filter condition
" is transformed into an extended condition for the join.
"- In the example, a specific 'carrid' value is filtered for. LEFT OUTER
" is specified as join type explicitly. Not specifying the join type here
" has the same effect. The 'fldate' value is only retrieved for 'DL'
" entries. The other ones have initial values.
SELECT carrid,
connid,
cityfrom,
cityto,
\_fli[ (*) LEFT OUTER WHERE carrid = 'DL' ]-fldate AS flightdate
"The following has the same effect in this example
"\_fli[ (*) WHERE carrid = 'DL' ]-fldate as flightdate
FROM zdemo_abap_cds_ve_assoc_e
ORDER BY carrid, connid, flightdate
INTO TABLE @DATA(assoc_attr_where).
output->display( input = assoc_attr_where name = `assoc_attr_where` ).
**********************************************************************
output->next_section( `9) ... WHERE clause` ).
"The following ABAP SQL SELECT statement uses a CDS view entity as
"the data source. The statement uses an exposed association.
"The SELECT list and the WHERE clause contain a path expression.
SELECT carrid,
connid,
countryfr,
countryto,
\_carr_exp-carrname
FROM zdemo_abap_cds_ve_assoc_e
WHERE \_carr_exp-carrid LIKE 'A_'
ORDER BY carrid, connid
INTO TABLE @DATA(assoc_exp_where).
output->display( input = assoc_exp_where name = `assoc_exp_where` ).
ENDMETHOD.
ENDCLASS.

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<?xml version="1.0" encoding="utf-8"?>
<abapGit version="v1.0.0" serializer="LCL_OBJECT_CLAS" serializer_version="v1.0.0">
<asx:abap xmlns:asx="http://www.sap.com/abapxml" version="1.0">
<asx:values>
<VSEOCLASS>
<CLSNAME>ZCL_DEMO_ABAP_CDS_VE</CLSNAME>
<LANGU>E</LANGU>
<DESCRIPT>ABAP cheat sheet: CDS view entities</DESCRIPT>
<STATE>1</STATE>
<CLSCCINCL>X</CLSCCINCL>
<FIXPT>X</FIXPT>
<UNICODE>5</UNICODE>
</VSEOCLASS>
</asx:values>
</asx:abap>
</abapGit>

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// ABAP CDS cheat sheet example:
// Aggregate expressions in the element list of CDS view entities
//
//////////////////////////------ NOTES ------//////////////////////////////////
// - CDS view entity selects from a demo database table
// - Demonstrates various aggregate expressions in the element list
// - As a prerequisite, run the class zcl_abap_demo_cds_ve to populate the
// database tables of the example. Otherwise, no data is displayed.
//
//////////////////////------ DATA PREVIEW ------///////////////////////////////
// - Choose F8 in ADT to open the data preview and check out the data displayed
// - For comparing and checking the output, you can also open the data preview
// for the database table. In ADT, press and hold CTRL and click the database
// table name. In the opened table artifact, choose F8 to open the data preview.
//
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////
@AccessControl.authorizationCheck: #NOT_REQUIRED
@EndUserText.label: 'CDS view entity: Aggregate expressions'
define view entity zdemo_abap_cds_ve_agg_exp
as select from zdemo_abap_fli
{
// The SELECT list intentionally includes few fields only to focus on the effect of aggregate expressions.
key carrid,
currency,
// -------- Aggregate expressions --------
// - Aggregate expressions can be used as elements of a SELECT list. Other positions are possible.
// - An alias name must be specified.
// - A GROUP BY clause is required. It must list all non-aggregated fields from the SELECT list.
// - Additions: If ALL is used, all rows in the result set are respected. This the default setting.
// If DISTINCT is used, only distinct values of an argument are respected.
// AVG (Returns the average value of an argument)
avg( seatsocc as abap.dec(15,2)) as avg_seats_occ,
avg( cast(paymentsum as abap.dec(15, 2)) as abap.dec(15,2)) as avg_paysum,
// SUM (Returns the sum of an argument)
// Since a currency field is used in the example, an annotatin is required.
@Semantics.amount.currencyCode: 'currency'
sum(paymentsum) as total_paysum,
// MIN (Returns the least value of an argument)
min( seatsocc ) as min_occ_seats,
// MAX (Returns the greatest value of an argument)
max( seatsocc ) as max_occ_seats,
max( all seatsocc ) as max_occ_seats_all, //Same result as above, ALL is optional
// COUNT (Returns counted lines)
count(*) as cnt, // * means that all lines are respected
count(distinct planetype) as cnt_planetype //DISTINCT means that the number of dinstinct values if an argument is counted;
//e.g. if 3 is returned, it means there are 3 different plane types among the result set
}
//GROUP BY clause that lists all non-aggregated fields from the SELECT list
group by
carrid,
currency

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{
"BASEINFO":
{
"FROM":
[
"ZDEMO_ABAP_FLI"
],
"ASSOCIATED":
[],
"BASE":
[],
"ANNO_REF":
[],
"SCALAR_FUNCTION":
[],
"VERSION":0,
"ANNOREF_EVALUATION_ERROR":""
}
}

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<?xml version="1.0" encoding="utf-8"?>
<abapGit version="v1.0.0" serializer="LCL_OBJECT_DDLS" serializer_version="v1.0.0">
<asx:abap xmlns:asx="http://www.sap.com/abapxml" version="1.0">
<asx:values>
<DDLS>
<DDLNAME>ZDEMO_ABAP_CDS_VE_AGG_EXP</DDLNAME>
<DDLANGUAGE>E</DDLANGUAGE>
<DDTEXT>CDS view entity: Aggregate expressions</DDTEXT>
<SOURCE_TYPE>W</SOURCE_TYPE>
</DDLS>
</asx:values>
</asx:abap>
</abapGit>

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// ABAP CDS cheat sheet example: Associations
//
//////////////////////////------ NOTES ------//////////////////////////////////
// - CDS view entity that selects from a demo CDS view entity and demonstrates
// associations. A selection of use cases of associations is covered. For
// more information and examples, see the ABAP Keyword Documentation.
// - As a prerequisite, run the class zcl_abap_demo_cds_ve to populate the
// database tables of the example. Otherwise, no data is displayed.
// - For further notes on associations, see the commented out information further
// down.
// - To see how the joins are realized on the database, you can right-click anywhere
// in the source code and choose 'Show SQL Create Statement'. The example
// includes associations where only left outer joins are performed.
//
//////////////////////------ DATA PREVIEW ------///////////////////////////////
// - Choose F8 in ADT to open the data preview and check out the data displayed
//
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////
@AccessControl.authorizationCheck: #NOT_REQUIRED
@EndUserText.label: 'CDS view entity: Associations 1'
define view entity zdemo_abap_cds_ve_assoc
// In this example, the data source, from which data is read, is another CDS view entity.
// This source CDS view entity selects all fields from the demo database table zdemo_abap_flsch.
// It also contains exposed associations that are used here.
as select from zdemo_abap_cds_ve_assoc_e as _flsch
// 1) One use case of assocations, which is not covered here, can be the use in the FROM clause.
// - That is, you can use an association as data source by specifying a path expression.
// - For example, the CDS view entity zdemo_abap_cds_ve_assoc_e exposes an association
// _carr_exp1. Therefore, a FROM clause as follows is possible:
// ... as select from zdemo_abap_cds_ve_assoc_e._carr_exp1 as _flsch ...
// 2) Adding fields of an association target to the element list (of the same CDS view entity)
// - In this case, since data is requested, a join is carried out.
// - The data preview (choose F8) shows the values for the added fields.
// - In this example, the association is used, but not exposed. Therefore, it cannot be used
// in path expressions in other CDS entities as shown in 3).
association [1..1] to zdemo_abap_carr as _carr1 on _flsch.Carrid = _carr1.carrid
association [1..1] to zdemo_abap_carr as _carr2 on _flsch.Carrid = _carr2.carrid
association [1..*] to zdemo_abap_fli as _fli on _flsch.Carrid = _fli.carrid
// 3) Exposing associations
// - In this example, no fields of the association target are added to the element list.
// But the assocation is exposed in the element list. Therefore, it can be used
// in path expressions in other CDS entities.
// - In this case, since data is not requested, a join is not carried out. It is up to
// to the consumer (e.g. an ABAP SQL statement or other CDS view entities) to request
// fields (one field, multiple fields, all fields ...). Only then, a join is performed.
// - The data preview (choose F8) does not show any data of the association target.
// - Compare the ON condition to the ones above. For demonstration purposes, the carrid
// field is specified with an alias name in the element list. To refer to this name,
// the prefix $projection. is required. As above, you can also use the original name.
association [1..1] to zdemo_abap_carr as _carr3 on $projection.carrier = _carr3.carrid
{
// Including fields from the data source
// The prefix _flsch. is actually not necessary here in the example. It's intentionally included to emphasize the data source.
key _flsch.Carrid as carrier,
key _flsch.Connid as connection_id,
_flsch.Cityfrom,
_flsch.Cityto,
// Regarding 2) Adding fields of an association target to the element list
// - Two fields are added in the element list.
// - You can make a right-click and choose 'Show SQL Create Statement' to check how the join is performed.
// - Because a left outer join is performed, the coalesce function is included for a field.
// If there are null values, the specified character literal is inserted.
// - Only these two fields are respected from the association target.
_carr1.carrname as carrier_name,
coalesce(_carr1.url, 'NULL') as carr_url,
// Regarding 3) Exposing associations
// - The association is exposed in the element list (but no fields of the association target).
// - As demonstrated in the executable class of this cheat sheet, an ABAP SQL statement
// can request data of the association target.
// - The data preview does not include any fields from the association target. Likewise,
// the 'SQL Create Statement' does not show any join with this assocation.
_carr3,
// 4) Using associations that are exposed in external views
// - The CDS view entity that is used as data source in the SELECT list exposes
// associations.
// - Such an association is used in a path expression here to include a field from the
// association target in the element list. In this case, this CDS view entity is
// a consumer of the association. A join is performed, as can be seen in the
// 'SQL Create Statement' view.
_flsch._carr_exp.currcode as curr_exposed,
// 5) Attributes of path expression
// - Attributes are specified in angle brackets after each CDS association to define
// further properties. These can be the cardinality, join type that is implemented when used,
// and filter conditions
// Speciying filter conditions and the join type
// - Only if a join type is specified explicitly, the addition WHERE must be specified
// - The example specifies the join type. Therefore, WHERE is required. Here in the example,
// the specification can also be the one commented out below because it implicitly has
// the same effect. Here, a left outer join is performed by default.
// - The operand specified on the left side of the condition must be a field of the association target.
_carr2[left outer where $projection.carrier = 'LH'].url as fcond_url,
//_carr2[$projection.carrier = 'LH'].url as fcond_url
// Specifying the cardinality of the current CDS association
// - The values 1: (current CDS association is declared as unique) and *: (non-unique) are possible.
// - You can use 1: to prevent a syntax warning in case of a path specified with filter conditions, for example.
// - In the example, an association is specified with to many (there can be multiple flights for a flight route).
// Without the cardinality specification 1:, a warning would be displayed ("The association _fli can modify
// the cardinality of the results set").
// - Similar to the example above, the first line commented out below is also possible in this example.
// The second line commented out results in a syntax warning because it does not specify the
// cardinality 1:.
_fli[1:$projection.connection_id = connid].fldate as fcond_fldate
//_fli[1:left outer where $projection.connection_id = connid].fldate as fcond_fldate
//_fli[$projection.connection_id = connid].fldate as fcond_fldate
}
////////////////////////// --------- Notes on associations --------- /////////////////////////////////////////
// - They offer an advanced modelling capability for CDS data models. They define relationships between
// CDS entities (association source and target). On the database, associations are internally transformed into joins.
// - Compared to regular joins, associations differ in the following respects:
// - Joins are only performed on demand, i.e. when data is requested from the assocation by a consumer, e.g.
// using another CDS view entity or an ABAP SQL statement. In the regular joins (e.g. inner, outer joins), the
// join is always performed. When a CDS association is instantiated as join on the database, the association
// source represents the left side and the association target represents the right side of the join.
// - In the SELECT list, specifying the data source as a prefix is mandatory for all fields of the association.
// For joins, it is mandatory only for for non-unique names.
// - Unlike regular joins, associations can be reused in different positions and basically replace very complex
// join expressions.
// - Use of associations:
// - Including fields from the association target in the current view
// - Exposing associations so that they can be used in other CDS entities or in ABAP SQL
// - Associations can be used in path expressions (a sequence of associations) at different operand positions.
// - Associations can be specified with additional semantic information, such as cardinality.
// - Specifying the (optional) cardinality is a means of documenting the semantics of the data model.
// - Cardinality is specified in square brackets [ ]. Minimum and maximum can be specified, for example
// one to one [1..1], one to many [1..*]. The default is [0..1]. Specifying the minimum value is optional (the
// default value is 0), i.e. [0..1] is [1], [0..*] is [*]. The minimum cannot be *, the maximum not 0.
// - Maximum values greater than 1 can lead to syntax errors or warnings. Generally, a non-matching cardinality
// usually produces a warning.
// - If the cardinality is not specified, it is to one by default [x..1].
// - Compositions and to-parent associations are special kinds of CDS associations. They are not covered in the example.

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{
"BASEINFO":
{
"FROM":
[
"ZDEMO_ABAP_CDS_VE_ASSOC_E",
"ZDEMO_ABAP_CARR",
"ZDEMO_ABAP_FLI"
],
"ASSOCIATED":
[
"ZDEMO_ABAP_CARR"
],
"BASE":
[],
"ANNO_REF":
[],
"SCALAR_FUNCTION":
[],
"VERSION":0,
"ANNOREF_EVALUATION_ERROR":""
}
}

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<?xml version="1.0" encoding="utf-8"?>
<abapGit version="v1.0.0" serializer="LCL_OBJECT_DDLS" serializer_version="v1.0.0">
<asx:abap xmlns:asx="http://www.sap.com/abapxml" version="1.0">
<asx:values>
<DDLS>
<DDLNAME>ZDEMO_ABAP_CDS_VE_ASSOC</DDLNAME>
<DDLANGUAGE>E</DDLANGUAGE>
<DDTEXT>CDS view entity: Associations</DDTEXT>
<SOURCE_TYPE>W</SOURCE_TYPE>
</DDLS>
</asx:values>
</asx:abap>
</abapGit>

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// ABAP CDS cheat sheet example: Associations
//
//////////////////////////------ NOTES ------//////////////////////////////////
// - CDS view entity that selects from a demo database table.
// - The purpose of this CDS view entity is to demonstrate associations. The view
// is used as a data source in another CDS view entity.
// - As a prerequisite, run the class zcl_abap_demo_cds_ve to populate the
// database tables of the example. Otherwise, no data is displayed.
//
//////////////////////------ DATA PREVIEW ------///////////////////////////////
// - Choose F8 in ADT to open the data preview and check out the data displayed
//
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////
@AccessControl.authorizationCheck: #NOT_REQUIRED
@EndUserText.label: 'CDS view entity: Associations'
define view entity zdemo_abap_cds_ve_assoc_e
as select from zdemo_abap_flsch as _flsch
association [1..1] to zdemo_abap_carr as _carr_exp on _flsch.carrid = _carr_exp.carrid
association [1..*] to zdemo_abap_fli as _fli on _flsch.carrid = _fli.carrid and _flsch.connid = _fli.connid
{
key _flsch.carrid as Carrid,
key _flsch.connid as Connid,
_flsch.countryfr as Countryfr,
_flsch.cityfrom as Cityfrom,
_flsch.airpfrom as Airpfrom,
_flsch.countryto as Countryto,
_flsch.cityto as Cityto,
_flsch.airpto as Airpto,
_flsch.fltime as Fltime,
_flsch.deptime as Deptime,
_flsch.arrtime as Arrtime,
_flsch.distance as Distance,
_flsch.distid as Distid,
_flsch.fltype as Fltype,
_flsch.period as Period,
_carr_exp,
_fli
}

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{
"BASEINFO":
{
"FROM":
[
"ZDEMO_ABAP_FLSCH"
],
"ASSOCIATED":
[
"ZDEMO_ABAP_CARR",
"ZDEMO_ABAP_FLI"
],
"BASE":
[],
"ANNO_REF":
[],
"SCALAR_FUNCTION":
[],
"VERSION":0,
"ANNOREF_EVALUATION_ERROR":""
}
}

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<?xml version="1.0" encoding="utf-8"?>
<abapGit version="v1.0.0" serializer="LCL_OBJECT_DDLS" serializer_version="v1.0.0">
<asx:abap xmlns:asx="http://www.sap.com/abapxml" version="1.0">
<asx:values>
<DDLS>
<DDLNAME>ZDEMO_ABAP_CDS_VE_ASSOC_E</DDLNAME>
<DDLANGUAGE>E</DDLANGUAGE>
<DDTEXT>CDS view entity: Associations</DDTEXT>
<SOURCE_TYPE>W</SOURCE_TYPE>
</DDLS>
</asx:values>
</asx:abap>
</abapGit>

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// ABAP CDS cheat sheet example: Joins
//
//////////////////////////------ NOTES ------//////////////////////////////////
// - CDS view entity selects from a demo database table
// - Demonstrates various joins
// - As a prerequisite, run the class zcl_abap_demo_cds_ve to populate the
// database tables of the example. Otherwise, no data is displayed.
// It is particularly needed in this case because it contains entries to
// visualize the effect of outer joins.
// - HOW TO:
// - To reduce the number of separate artifacts, this example CDS view entity
// contains the code for multiple joins, which is commented out.
// - To test out various joins, you can comment out and comment in the
// respective code sections (select the lines and choose CTRL + 7).
// - The example for inner joins is commented in by default. The relevant
// code sections are marked with "COMMENT IN/OUT ... START" and
// "COMMENT IN/OUT ... START" in both SELECT and element list
// (inner joins -> 1a / 1b). To test the left outer joins, for example,
// comment out the respective sections of the inner join and comment in
// the sections for left outer joins (2a, 2b), and so on.
// - Once done, activate the view and choose F8 to open the data preview.
// You must activate the view and choose F8 again for every change here
// because the alias names are different.
//
//////////////////////------ DATA PREVIEW ------///////////////////////////////
// - Choose F8 in ADT to open the data preview and check out the data displayed
// - Note the hints above regarding commenting in/out of code.
//
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////
@AccessControl.authorizationCheck: #NOT_REQUIRED
@EndUserText.label: 'CDS view entity: Joins'
define view entity zdemo_abap_cds_ve_joins
as select from zdemo_abap_carr as _carr
// Notes on joins:
// - Joins combine two data sources into one result set, consisting of columns of both data sources
// - Rows of the result set are determined by the join type and by join conditions between columns of the data sources
// - Joins can be nested
// - Inner or outer join must contain a join condition after ON
// - Each element of the SELECT list must have the name of its data source as prefix
// - When joins are used, a WHERE condition affects the result set
// - The cardinality can be specified for left outer joins. For more details, see the ABAP Keyword Documentation.
/////////////////// ----- Example for INNER JOIN ----- /////////////////////////////////
// Notes:
// - Joins all entries of the data sources whose fields match the ON condition
// - In the table zdemo_abap_carr, there are entries in carrid that are not present in zdemo_abap_flsch.
// The same is true the other way round. The result only contains those entries that exist in both data sources
// based on the ON condition.
//// ----> COMMENT IN/OUT 1a START <-----
inner join zdemo_abap_flsch as _flsch_in on _carr.carrid = _flsch_in.carrid
//// ----> COMMENT IN/OUT 1a END <-----
//Alternative syntax: Specifying 'inner' is optional
// join zdemo_abap_flsch
// as _flsch_in on _carr.carrid = _flsch_in.carrid
/////////////////// ----- Example for LEFT OUTER JOIN ----- /////////////////////////////////
// Notes:
// - The join selects all entries on the left side. Entries that match the ON condition have the same content as in the inner join.
// In entries that do not match the ON condition, the elements on the right side have the null value.
// - To demonstrate the effect, the table zdemo_abap_carr contains entries for carrid that are not present in zdemo_abap_flsch.
// - Example in the SELECT list:
// - The coalesce function can be used to prevent null values in the result set.
// - In the example, the function is used for an element to prevent null values.
//// ----> COMMENT IN/OUT 2A START <-----
// left outer join zdemo_abap_flsch as _flsch_lo on _carr.carrid = _flsch_lo.carrid
//// ----> COMMENT IN/OUT 2A END <-----
/////////////////// ----- Example for RIGHT OUTER JOIN ----- /////////////////////////////////
// Notes:
// - The join selects all entries on the right side. Entries that match the ON condition have the same content as in the inner join.
// In entries that do not match the ON condition, the elements on the left side have the null value.
// - To demonstrate the effect, the table zdemo_abap_carr contains entries for carrid that are not present in zdemo_abap_flsch.
// - Example in the SELECT list:
// - Instead of the coalesce function, you can also use a CASE expression using a logical expression with IS [NOT] NULL
// to prevent null values in the result set.
// - In the example, a CASE expression is used for an element to prevent null values.
//// ----> COMMENT IN/OUT 3A START <-----
// right outer join zdemo_abap_flsch as _flsch_ro on _carr.carrid = _flsch_ro.carrid
//// ----> COMMENT IN/OUT 3A END <-----
/////////////////// ----- Example for CROSS JOIN ----- /////////////////////////////////
// Notes:
// - All entries on the left side are combined with all entries on the right side.
// - It is not possible to specify an ON condition.
//- The number of lines of the result is the number of left lines multiplied by the number of lines of the right table.
//// ----> COMMENT IN/OUT 4A START <-----
// cross join zdemo_abap_flsch as _flsch_cr
//// ----> COMMENT IN/OUT 4A END <-----
{
key _carr.carrid,
_carr.carrname,
/////////////////// ----- Example for INNER JOIN ----- /////////////////////////////////
// ----> COMMENT IN/OUT 1b START <-----
_flsch_in.cityfrom as cityfr_in,
_flsch_in.cityto as cityto_in
// ----> COMMENT IN/OUT 1b END <-----
/////////////////// ----- Example for LEFT OUTER JOIN ----- /////////////////////////////////
//// ----> COMMENT IN/OUT 2b START <-----
// _flsch_lo.cityfrom as cityfr_lo,
// coalesce(_flsch_lo.cityto, '???') as cityto_lo
//// ----> COMMENT IN/OUT 2b END <-----
/////////////////// ----- Example for RIGHT OUTER JOIN ----- /////////////////////////////////
//// ----> COMMENT IN/OUT 3b START <-----
// case when _carr.url is not null then _carr.url
// else '!!!'
// end as url_ro,
// _flsch_ro.cityfrom as cityfr_ro,
// _flsch_ro.cityto as cityto_ro
//// ----> COMMENT IN/OUT 3b END <-----
/////////////////// ----- Example for CROSS JOIN ----- /////////////////////////////////
//// ----> COMMENT IN/OUT 4b START <-----
// _flsch_cr.cityfrom as cityfr_cr,
// _flsch_cr.cityto as cityto_cr
//// ----> COMMENT IN/OUT 4b END <-----
}

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{
"BASEINFO":
{
"FROM":
[
"ZDEMO_ABAP_CARR",
"ZDEMO_ABAP_FLSCH"
],
"ASSOCIATED":
[],
"BASE":
[],
"ANNO_REF":
[],
"SCALAR_FUNCTION":
[],
"VERSION":0,
"ANNOREF_EVALUATION_ERROR":""
}
}

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<?xml version="1.0" encoding="utf-8"?>
<abapGit version="v1.0.0" serializer="LCL_OBJECT_DDLS" serializer_version="v1.0.0">
<asx:abap xmlns:asx="http://www.sap.com/abapxml" version="1.0">
<asx:values>
<DDLS>
<DDLNAME>ZDEMO_ABAP_CDS_VE_JOINS</DDLNAME>
<DDLANGUAGE>E</DDLANGUAGE>
<DDTEXT>CDS view entity: Joins</DDTEXT>
<SOURCE_TYPE>W</SOURCE_TYPE>
</DDLS>
</asx:values>
</asx:abap>
</abapGit>

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// ABAP CDS cheat sheet example:
// Operands and expressions in CDS view entities
//
//////////////////////////------ NOTES ------//////////////////////////////////
// - CDS view entity selects from a demo database table
// - Demonstrates various syntax options regarding operands and expressions
// - As a prerequisite, run the class zcl_abap_demo_cds_ve to populate the
// database tables of the example. Otherwise, no data is displayed.
//
//////////////////////------ DATA PREVIEW ------///////////////////////////////
// - Choose F8 in ADT to open the data preview and check out the data displayed
// - The example includes parameters. Therefore, you are prompted to insert a
// value. In this example, the parameter (maximum seats in a plane) is used for
// the WHERE clause (the lower the number entered, the more entries in the result
// set).
//
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////
//////////////////////------ Annotations ------///////////////////////////////
// Annotations add metadata to a CDS object that expands the syntax options of SQL.
// There's a predefined set of SAP annotations. Their specification is optional.
// Example for a view entity annotation (only possible in CDS view entities)
// The following annotation defines implicit access control when ABAP SQL is used
// to access the CDS view entity. Here, it is determined that no access control
// is required.
@AccessControl.authorizationCheck: #NOT_REQUIRED
// Example for an entity annotation (annotations that can be used in all CDS entities)
// The following annotation provdes a translatable short text of the CDS entity.
@EndUserText.label: 'CDS view entity: Operands/Expressions'
define view entity zdemo_abap_cds_ve_sel
with parameters
p_smax : abap.int4 //Input parameter typed with an elementary data type;
//can also be a DDIC data element
as select from zdemo_abap_fli //Selection from a demo database table;
//an alias name can be also specified ... as _fli, for example
// The following SELECT list demonstrates possible elements, operands and expressions.
// Note: Many of the operands and expressions demonstrated below can occur in multiple positions.
// Refer to the ABAP Keyword Documentation for the details.
{
// -------- Specifying fields of the data source --------
//- Multiple fields of the data source from which to be selected are specified.
//- Field names can be prefixed with the name of the data source (or, if specified, with the alias name).
//- Alias names can be specified for the elements. Note: In case of joins (selection from multiple sources)
// all elements must be prefixed with the name of the data source. See the view entity demonstrating joins.
//- KEY defines the current element as a key element; must be placed at the beginning; in CDS entities the key
// elements are mainly used to document the semantics of the data model (Note: They do not define unique lines
// in its result with regard to the key.)
key carrid as CarrierId, //Alias name specified
key zdemo_abap_fli.connid as Connid, //Element prefixed with data source; alias name specified
key fldate,
price,
currency,
paymentsum,
planetype,
seatsmax,
seatsocc,
// -------- Literals --------
// Typed literals (cover most built-in types of the ABAP Dictionary)
// As is true for all of the following elements, an alias name must be specified.
abap.int4'12345' as int4, //Typed numeric literal
abap.char'hallo' as c5, //Typed character literal
abap.dats'20240101' as date_lit, //Date
// Note: In case of a currency or quantity field specified with a typed literal, a reference
// to a currency key or unit is mandatory, which requires an annotation. The currency example
// here uses the following annotation. The element 'currency' from above is referenced.
@Semantics.amount.currencyCode: 'currency'
abap.curr'12.34' as curr,
abap.dec'0.9' as discnt,
abap.unit'KM' as kilometers,
// Untyped literals
'Minutes' as fltime_ut, //Untyped character literal
1 as num_lit, //Untyped numeric literal
// -------- Parameters --------
// Parameters can be specified in an operand position.
// The name of the parameter must be prefixed by $parameters.
$parameters.p_smax as param,
// -------- Session variables --------
// Among other sesion variables, there are built-in session variables available.
$session.user as usr,
$session.client as clnt,
$session.system_language as langu,
$session.system_date as sys_date,
$session.user_timezone as usr_time,
$session.user_date as usr_date,
// -------- Expressions --------
//Note: Aggregate and path expressions are covered in a separate CDS view entity.
// -------- Cast expressions --------
// Convert the value of operands to a specified type after as
// The examples use built-in data types only.
// Note: Regarding which conversion combinations of types are possible, see the ABAP Keyword Documentation.
// There are special conversion rules for every combination.
cast( price as abap.dec(15,2) ) as cast_curr2dec,
// The following example uses the prefix $projection. which defines reuse expressions.
// That is, you can refer to an element defined previously in the SELECT list of the same CDS view entity.
// Note that this is only possible in dedicated positions. One of them is a cast expression.
//cast( $projection.date_lit as abap.int4 ) as cast_dats,
//cast( $projection.curr as abap.int4 ) as cast_curr,
cast( $projection.date_lit as abap.char(8) ) as cast_dats2c,
// -------- Arithmetic expressions --------
seatsocc_b + seatsocc_f as occ_seats_classes,
seatsmax - seatsocc as free_seats,
2 * 2 as mult,
9 / 3 as div,
//Arithmetic expressions using cast and reuse expressions
cast( paymentsum as abap.dec(17,2) ) * abap.dec'0.75' as discount_1,
$projection.cast_curr2dec * $projection.discnt as discount_2,
cast( seatsocc / seatsmax * 100 as abap.dec(10, 2) ) as occupancy_rate,
// -------- Case expressions --------
// Simple case distinction for comparing values of operands with other operands.
// The first operand specified after THEN for which the comparison is true is
// returned as a result. No match: Result is determined by the ELSE branch.
case currency
when 'EUR' then 'X'
when 'USD' then 'Y'
else 'Z'
end as case1,
// In newer ABAP releases, you can use the ELSE NULL addition that returns the null value.
// Note: If ELSE is not specified, the null value is returned as a result.
// case $projection.case1
// when 'X' then 'A'
// else null
// end as case2,
// Complex case distinction (searched case) for evaluating conditions
case
when seatsmax <= 150 then 'small'
when seatsmax > 150 and seatsmax < 300 then 'middle'
when seatsmax >= 300 then 'large'
else '?'
end as case3,
// -------- Excursion: Logical expressions --------
// The following nonsense example using a CASE expression just visualizes the rich variety of options.
//Comparison operators
// Boolean operators AND, OR, NOT as well as parenthesized expressions are possible.
case
when seatsmax = 385 and not ( seatsocc > 380 and seatsocc <> 379 or seatsocc <= 120 or paymentsum >= 200000 ) then 'A'
//Interval comparisons
when seatsmax between 250 and 350 and seatsocc not between 1 and 100 then 'B'
//Pattern comparisons ('%' -> wildcard character, represents any character string, '_' -> stands for any character)
when carrid like '_L' then 'C'
//Checking for null and initial value
when currency is not null or carrid is not initial then 'D'
else '?'
end as case4,
// -------- Built-in functions --------
// SQL functions (only a selection is covered here)
// Numeric functions
// The example uses typed and untyped literals only as arguments.
abs( abap.int4'-1' ) as nf_abs,
ceil( abap.decfloat34'3.333' ) as nf_ceil,
floor( abap.decfloat34'3.333' ) as nf_floor,
div( 25, 5 ) as nf_div,
mod( 11, 3 ) as nf_mod,
division( 1, 3, 2 ) as nf_division,
round( abap.decfloat34'1.337', 2 ) as nf_round,
// String functions
concat(planetype, '-#') as sf_concat,
concat_with_space(carrid, '#', 1) as sf_conc_ws, //3rd argument: number of spaces
instr(currency, 'U') as sf_instr, //Position of the first occurrence of the string from the substring in the argument (case-sensitive)
left(currency, 2) as sf_left, //String of length n starting from the left of an expression
length(planetype) as sf_len, //Number of characters in an argument ignoring trailing blanks
lower(carrid) as sf_lower, //String with a length of an argument in which all uppercase letters are transformed to lowercase letters
lpad(carrid, 5, '#') as sf_lpad, //String of a length with the right-aligned content of an argument without trailing blanks and in which leading blanks produced by the expanded string are replaced by the characters from an argument (respecting all blanks)
ltrim(planetype, 'A') as sf_ltrim, //String with the content of an argument in which all trailing blanks and leading characters are removed that match the specified character.
replace(currency, 'U', '#') as sf_repl, //String in which all instances of the second argument are replaced by the content from the third argument
replace_regexpr(PCRE => '\\d', //More optional parameters are possible; the example replaces all digits
VALUE => planetype,
WITH => '#',
RESULT_LENGTH => 10) as sf_repl_regex,
right(currency, 2) as sf_right, //String of length n starting from the right of an expression
rpad(carrid, 5, '#') as sf_rpad, //See lpad; here, right-algined content
rtrim(planetype, '0') as sf_rtrim, //See ltrim; here, from the right
substring(planetype, 4, 3) as sf_sub, //Returns a substring; second argument: position from where to start; third argument: length of the extracted substring
upper( 'abap' ) as sf_upper, //Transforms to upper case
// Coalesce function
// Checks whether the argument contains a null value. If it contains it, it returns the value of the second argument
// Otherwise, it returns the value of the first argument.
// This example has no null values in carrid, therefore the carrid value is output. See the example view about joins.
coalesce(carrid, 'N') as coalesced,
// Special functions
// Type conversion functions
fltp_to_dec( abap.fltp'12.34' as abap.dec(10,1) ) as fltp2dec,
// Unit conversion
// In the following example, the number that is input as parameter is used as the value for a distance in miles. It is converted to kilometers.
@Semantics.quantity.unitOfMeasure: 'kilometers'
unit_conversion( quantity => $parameters.p_smax,
source_unit => abap.unit'MI',
target_unit => $projection.kilometers ) as converted_value,
// Date/Time functions
// The function in the example calculates the days between to dates. The actual parameters must have the built-in data type DATS.
dats_days_between(fldate,$projection.date_lit) as days_bw1,
// The following example is similar to the example above. Here, the function expects the type DATN.
// It also shows the use of another function (dats_to_datn) that converts the types.
// Note: Only literals can be passed to the final two parameters on_error, on_initial.
datn_days_between(dats_to_datn(fldate,'INITIAL','INITIAL') , dats_to_datn($session.user_date,'INITIAL','INITIAL')) as days_bw2,
// The following function adds days to a date. Here, the date a week from today is calculated.
dats_add_days($session.user_date,7,'INITIAL') as in1week,
// Time stamp functions
// Getting the current time stamp
utcl_current() as ts,
// Adding seconds to a time stamp
utcl_add_seconds($projection.ts,60) as in1minute
}
// -------- Clauses for the SELECT statement --------
// SELECT statements of a CDS view entitiy can be specified with optional clauses
// Among them, there are WHERE (to restrict the rows of the result set), GROUP BY (grouping the result set(
// HAVING (further restriction after the GROUP BY clause) clauses and other set operators like EXCEPT, INTERSECT and UNION.
// This example uses a simple WHERE clause. It uses a condition that includes the input parameter to restrict the result set.
where seatsmax > $parameters.p_smax

19
src/zdemo_abap_cds_ve_sel.ddls.baseinfo Normal file
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{
"BASEINFO":
{
"FROM":
[
"ZDEMO_ABAP_FLI"
],
"ASSOCIATED":
[],
"BASE":
[],
"ANNO_REF":
[],
"SCALAR_FUNCTION":
[],
"VERSION":0,
"ANNOREF_EVALUATION_ERROR":""
}
}

13
src/zdemo_abap_cds_ve_sel.ddls.xml Normal file
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<?xml version="1.0" encoding="utf-8"?>
<abapGit version="v1.0.0" serializer="LCL_OBJECT_DDLS" serializer_version="v1.0.0">
<asx:abap xmlns:asx="http://www.sap.com/abapxml" version="1.0">
<asx:values>
<DDLS>
<DDLNAME>ZDEMO_ABAP_CDS_VE_SEL</DDLNAME>
<DDLANGUAGE>E</DDLANGUAGE>
<DDTEXT>CDS view entity: Operands and expressions</DDTEXT>
<SOURCE_TYPE>W</SOURCE_TYPE>
</DDLS>
</asx:values>
</asx:abap>
</abapGit>