33 lines
1.2 KiB
JavaScript
33 lines
1.2 KiB
JavaScript
const cds = require('@sap/cds/lib')
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if (cds.requires.db?.kind === 'sqlite') {
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// Add a column to the Genres table, to efficiently determine if a node
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// is a leaf, and use it for DrillState in hierarchy queries.
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cds.on('loaded', m => Object.assign (
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m.definitions['sap.capire.bookshop.Genres'].elements,
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cds.parse (`entity Genres {
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DrillState: String = coalesce(leaf,'collapsed');
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leaf: String;
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}`).definitions.Genres.elements
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))
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// Fill in `leaf` helper column for initial data entries
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cds.on('served', ()=> cds.run(`
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UPDATE sap_capire_bookshop_Genres as g SET leaf='leaf' WHERE not exists (
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SELECT 1 from sap_capire_bookshop_Genres WHERE parent_ID = g.ID
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)`
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))
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// Register a simplistic handler for hierarchical queries
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cds.on('serving:AdminService', srv => srv.prepend(() => srv.on('READ', 'Genres', (req,next) => {
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const q = req.query, parent = {ref:['parent','ID']}
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if (q.SELECT.recurse?.where?.[0].ref[0] === 'Distance') q.SELECT.where[0] = parent
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else if (!q.SELECT.search) q.SELECT.where ??= [ parent, 'is null' ]
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// Suppress error message: Feature "recurse" queries not supported.
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delete q.SELECT.__proto__.recurse
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delete q.SELECT.recurse
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return next()
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})))
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}
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