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<a name="top"></a>
# A Glimpse on AMDP
- [A Glimpse on AMDP](#a-glimpse-on-amdp)
- [About AMDP](#about-amdp)
- [AMDP Classes](#amdp-classes)
- [AMDP Methods](#amdp-methods)
- [AMDP Procedures](#amdp-procedures)
- [AMDP Functions](#amdp-functions)
- [CDS Table Functions](#cds-table-functions)
- [Further Information](#further-information)
- [Executable Example](#executable-example)
This cheat sheet gathers basic information on [ABAP Managed Database
Procedures
(AMDP)](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenabap_managed_db_proc_glosry.htm "Glossary Entry").
Find more details
[here](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenamdp.htm)
in the ABAP Keyword Documentation.
## About AMDP
- AMDP are a class-based framework for managing and calling
- [database
procedures](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abendatabase_procedure_glosry.htm "Glossary Entry")
(which is a synonym for [stored
procedures](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenstored_procedure_glosry.htm "Glossary Entry"), i.
e. the procedures are stored in the database - the [SAP HANA
database](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenhana_database_glosry.htm "Glossary Entry")
in this case - and executed there)
- [database
functions](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abendatabase_function_glosry.htm "Glossary Entry")
(which are [SQLScript
functions](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abensql_script_function_glosry.htm "Glossary Entry")
in the SAP HANA database)
in [AS ABAP](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenas_abap_glosry.htm "Glossary Entry").
- "ABAP managed" enters the picture in ABAP with the option of
implementing special [AMDP
procedures](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenamdp_procedure_glosry.htm "Glossary Entry")
as database procedures and [AMDP
functions](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenamdp_function_glosry.htm "Glossary Entry")
as database functions.
- The implementations are programmed using a database-specific
language. Currently, AMDP only supports database procedures and
functions from the SAP HANA database. That is,
[SQLScript](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abensql_script_glosry.htm "Glossary Entry")
is the programming language of choice.
- AMDP procedures and functions are part of a dedicated [AMDP
class](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenamdp_class_glosry.htm "Glossary Entry")
and declared and implemented as part of a method. The classes and
methods have certain characteristics as outlined further down.
- The AMDP framework replicates the procedure or function to the
database system, i. e. despite the fact that the programming happens
in an AMDP class (which is an [ABAP
Repository](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenabap_repository_glosry.htm "Glossary Entry")
object as other global classes, too), the (SQLScript) code is
executed only on the (SAP HANA) database and not in AS ABAP, i. e.
method calls are sent to the database procedure or function.
> **💡 Note**<br>
>- The use of AMDP is not recommended if the same task can be
achieved using [ABAP
SQL](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenabap_sql_glosry.htm "Glossary Entry").
>- AMDP classes can only be edited with the [ABAP Development Tools
(ADT)](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenadt_glosry.htm "Glossary Entry").
## AMDP Classes
- As mentioned above, an [AMDP
class](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenamdp_class_glosry.htm "Glossary Entry")
is an [ABAP
Repository](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenabap_repository_glosry.htm "Glossary Entry")
object like other global classes.
- However, an AMDP class includes the specification of the interface
`IF_AMDP_MARKER_HDB` for the SAP HANA
database (indicated by `HDB`), which is currently the
only possible database.
- An AMDP class can contain both (one or more) [AMDP
methods](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenamdp_method_glosry.htm "Glossary Entry")
and non-AMDP methods.
Example for a [declaration part](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abendeclaration_part_glosry.htm "Glossary Entry")
of an AMDP class:
```abap
CLASS cl_some_amdp_class DEFINITION
  PUBLIC
  FINAL
  CREATE PUBLIC.
  PUBLIC SECTION.
    "Specifying the interface is mandatory
    INTERFACES if_amdp_marker_hdb.
...
ENDCLASS.
```
## AMDP Methods
- Can be created as [instance
methods](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abeninstance_method_glosry.htm "Glossary Entry")
using <code>METHODS</code> or [static
methods](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenstatic_method_glosry.htm "Glossary Entry")
using <code>CLASS-METHODS</code> in any visibility section.
- Cannot be identified as AMDP methods in the declaration part of the
class since there are no specific additions to the methods.
Exceptions: AMDP function implementations that implement any [CDS table functions](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abencds_table_function_glosry.htm "Glossary Entry")
as shown further down and method declarations using [`AMDP
OPTIONS`](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abapmethods_amdp_options.htm)
that are not dealt with here.
AMDP method declarations in any visibility section like non-AMDP
methods:
```abap
...
PUBLIC SECTION.
  METHODS some_amdp_meth
    ... "Here go the parameters
PRIVATE SECTION.
  CLASS-METHODS another_amdp_meth
    ... "Here go the parameters
...
```
## AMDP Procedures
Despite the fact that AMDP methods cannot be identified as such from the
[declaration
part](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abendeclaration_part_glosry.htm "Glossary Entry")
(apart from the exceptions mentioned above), the declaration part of
[AMDP
procedures](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenamdp_procedure_glosry.htm "Glossary Entry")
has special characteristics:
- Parameters must be [passed by
value](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenpass_by_value_glosry.htm "Glossary Entry")
using <code>VALUE(...)</code>. [Passing by
reference](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenpass_by_reference_glosry.htm "Glossary Entry")
is not allowed.
- Parameter types ...
- must not be generic.
- can only be [elementary data
types](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenelementary_data_type_glosry.htm "Glossary Entry")
and [table
types](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abentable_type_glosry.htm "Glossary Entry")
with a structured row type (and this type can only contain
elementary data types as components).
- Return values cannot be declared using <code>RETURNING</code>.
- Only input parameters can be flagged as optional parameters.
Example for an AMDP procedure's declaration part:
```abap
...
PUBLIC SECTION.
  "Table type with a structured row type
  TYPES tab_type TYPE STANDARD TABLE OF dbtab WITH EMPTY KEY.
  METHODS amdp_meth
    IMPORTING VALUE(num) TYPE i,
    EXPORTING VALUE(tab) TYPE tab_type.
...
```
In contrast to the declaration part, the [implementation
part](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenamdp_procedure_method_glosry.htm "Glossary Entry")
of an AMDP method has multiple special additions for AMDP purposes
following <code>METHOD</code> and the method name:
```abap
...
METHOD amdp_meth
BY DATABASE PROCEDURE
  FOR HDB  
  LANGUAGE SQLSCRIPT  
  OPTIONS READ-ONLY
  USING db_object. "see comments further down
                  
"Beginning of the SQLScript code (note that it is not ABAP code although it looks similar)
  ... "Here goes SAPScript code
      "Note that an AMDP method implementation must not be empty.
"End of the SQLScript code
ENDMETHOD.
...
"Comments:
" BY DATABASE PROCEDURE -> Flags the AMDP method as AMDP procedure
" FOR HDB   -> Definess the database system where the method is to be used;
"             currently, only HDB (SAP HANA database) is possible
" LANGUAGE SQLSCRIPT   -> Defines the programming language of the database system
" OPTIONS READ-ONLY -> Specifies database-specific options
" USING db_object. -> Optional addition; specifies database objects;
"                    can also be AMDP procedures and functions
```
Note:
- In the [restricted ABAP language
version](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenrestricted_version_glosry.htm "Glossary Entry")
scope, only reads are allowed. Hence, the addition `OPTIONS READ-ONLY` is mandatory. Furthermore, you must make sure
that the database objects that are specified after `USING` are accessible.
- Generally, in the [unrestricted ABAP language
version](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenunrestricted_version_glosry.htm "Glossary Entry")
scope, more syntax options are allowed for AMDP method declaration
and implementation parts. Check the ABAP Keyword Documentation for
more details as touched on further down.
## AMDP Functions
[Scalar](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenamdp_scalar_function_glosry.htm "Glossary Entry")
and [table
functions](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abentable_function_glosry.htm "Glossary Entry")
can be managed as [AMDP
functions](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenamdp_function_glosry.htm "Glossary Entry").
Such [AMDP table
functions](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenamdp_table_function_glosry.htm "Glossary Entry")
have, as the name implies, a tabular [return
value](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenreturn_value_glosry.htm "Glossary Entry")
whereas AMDP scalar functions have a scalar or elementary return value
(more information
[here](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenamdp_function_methods.htm)).
Regarding AMDP table functions, there are two types available:
- Functions that can only be accessed in other AMDP methods (i. e.
other AMDP functions or procedures) and cannot be called directly in
ABAP
- Functions that implement [CDS table
functions](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abencds_table_function_glosry.htm "Glossary Entry")
that can be accessed in ABAP SQL
Characteristics of method declaration parts of AMDP functions:
- Similar to AMDP procedures, the methods can be declared as static or
instance methods in any visibility section.
- The method parameters must include a return value using
<code>RETURNING</code> and having a tabular data type.
- Additionally, the parameters can include elementary and tabular
input parameters.
- No class-based exceptions can be declared using <code>RAISING</code>.
Example for an AMDP function's declaration part:
```abap
...
PUBLIC SECTION.
  "Table type with a structured row type
  TYPES tab_type TYPE STANDARD TABLE OF dbtab WITH EMPTY KEY.
  METHODS amdp_func
    IMPORTING VALUE(num)       TYPE i,
              VALUE(some_elem) TYPE c LENGTH 3,
    RETURNING VALUE(tab)       TYPE tab_type.
...
```
The implementation part of an AMDP function is similar to the one of
AMDP procedure as shown above. The difference is the use of `BY DATABASE FUNCTION` instead of `BY DATABASE PROCEDURE`:
```abap
...
METHOD amdp_func
  BY DATABASE FUNCTION    
  FOR HDB
  LANGUAGE SQLSCRIPT
  OPTIONS READ-ONLY
  USING db_object.
"Beginning of the SQLScript code (note that it is not ABAP code although it looks similar)
  ... "Here goes SAPScript code;
      "AMDP table function to be called by other AMDP methods only
"End of the SQLScript code
ENDMETHOD.
"Comment:
"  BY DATABASE FUNCTION    -> Flags the AMDP method as AMDP function
...
```
### CDS Table Functions
- Each [CDS table
function](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abencds_table_function_glosry.htm "Glossary Entry")
is linked with an AMDP function in which it is implemented using
SQLScript.
- Can be used as data sources of ABAP SQL read statements.
- Characteristics for method declaration and implementation parts
regarding AMDP functions for CDS table functions:
- Method can only be declared as a static method in the public visibility section of
an AMDP class using `CLASS-METHODS`.
- For the declaration, there is a special form with the addition
`FOR TABLE FUNCTION`.
- The [parameter
interface](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenparameter_interface_glosry.htm "Glossary Entry")
is not specified. Instead, the input parameters are determined
by the [input
parameters](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abeninput_parameter_glosry.htm "Glossary Entry")
of the CDS table function (i. e. the names and data types -
which are always elementary - specified there are used). As the
return value, a standard table with an empty key is generated
based on the structured row type including the components as
specified in the CDS table function.
Example for an AMDP functions declaration implementing a CDS table
function:
```abap
...
PUBLIC SECTION.
  CLASS-METHODS:
    table_func FOR TABLE FUNCTION some_ddl_source.
...
```
Notes on the [CDS
DDL](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abencds_ddl_glosry.htm "Glossary Entry")
source of a CDS table function:
- You have defined (and activated) a CDS DDL source, i. e. a [CDS
entity](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abencds_entity_glosry.htm "Glossary Entry"),
with the notation `DEFINE TABLE FUNCTION`
- You can specify optional input parameters using `... WITH PARAMETERS parameter1, parameter2, ...`
- You must specify an element list using `... RETURNS { element1; element2; ...; } ...`. The elements determine the
components of the structured data type represented by a CDS table
function.
- You have specified the `IMPLEMENTED BY METHOD` addition
followed by a fully qualified method name in the form of
`amdp_class=>amdp_method` using the names of the AMDP
class and method.
- More information
[here](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abencds_table_functions.htm).
The CDS DDL source might look like this:
```abap
//Here go annotations.
define table function some_ddl_source
  returns
  {
    client : abap.clnt;
    field1 : abap.char(5);
    field2 : abap.char(5);
  }
  implemented by method amdp_class=>amdp_method;
```
You can then use the CDS table function as source for a
`SELECT` statement, for example: `SELECT * FROM some_ddl_source INTO ...`.
## Further Information
Notes on using AMDP in environments with restricted language version (in
contrast unrestricted language version):
AMDP methods ...
- must include the addition <code>OPTIONS READ-ONLY</code> in the
declaration part.
- must be implemented in SQLScript in any case.
- cannot use the additions [`USING SCHEMA` (F1 for docu standard ABAP)](https://help.sap.com/doc/abapdocu_latest_index_htm/latest/en-US/index.htm?file=abapmethod_by_db_proc.htm#!ABAP_ADDITION_5@5@)
and [`SUPPRESS SYNTAX ERRORS` (F1 docu for standard ABAP)](https://help.sap.com/doc/abapdocu_latest_index_htm/latest/en-US/index.htm?file=abapmethod_by_db_proc.htm#!ABAP_ADDITION_3@3@)
in the method implementation part
- cannot use [AMDP
macros](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenamdp_macros.htm)
and call hints.
- can only use your own entities and entities that are released for
the restricted language version after <code>USING</code>.
- cannot use
[`CONNECTION` (F1 docu for standard ABAP)](https://help.sap.com/doc/abapdocu_latest_index_htm/latest/en-US/index.htm?file=abenamdp_db_connections.htm)
parameters.
- cannot raise the
`CX_AMDP_CONNECTION_ERROR` exception since
the `CONNECTION` parameter is not allowed.
As mentioned above and hinted in the bullet points above, AMDP has more
options regarding the unrestricted language version. Check the subtopics
[here](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenamdp.htm).
A fundamental question in on-premise ABAP systems with an unrestricted
language scope can be whether AMDP is supported at all. The constant
`CALL_AMDP_METHOD` of the class
`CL_ABAP_DBFEATURES` can be used to query
whether the current database supports AMDP methods. See the following
snippet:
```abap
IF NOT cl_abap_dbfeatures=>use_features(
   EXPORTING requested_features =
        VALUE #( ( cl_abap_dbfeatures=>call_amdp_method ) ) ).
  "Result: Current database system does not support AMDP procedures
  RETURN.
ENDIF.
```
This check is not required (and possible) for the SAP BTP ABAP Environment since those
environments are SAP HANA-only anyway and database connections are not
possible. Furthermore, another topic that should be noted is that AMDP
does not support [implicit client
handling](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenabap_sql_client_handling.htm).
Therefore, the parameter interface of AMDP methods usually contains an
input parameter for the client ID. See more information
[here](https://help.sap.com/doc/abapdocu_cp_index_htm/CLOUD/en-US/index.htm?file=abenamdp_client_handling.htm) (or [here for the F1 docu for standard ABAP](https://help.sap.com/doc/abapdocu_latest_index_htm/latest/en-US/index.htm?file=abenamdp_client_handling.htm)).
The client handling is not dealt with in this cheat sheet and not
relevant in the executable example.
## Executable Example
[zcl_demo_abap_amdp](./src/zcl_demo_abap_amdp.clas.abap)
Note the steps outlined [here](README.md#-getting-started-with-the-examples) about how to import and run the code.