feat: sort selected columns & expands before formatting sql

hana/lib/HANAService.js

@@ -531,6 +531,12 @@ class HANAService extends SQLService {
     SELECT_columns(q) {
       const { SELECT, src } = q
       if (!SELECT.columns) return '*'
+
+      // Sort selected columns to avoid creating redundant execution plans (column names can't be equal)
+      SELECT.columns = SELECT.columns.sort((a, b) => {
+        return (typeof a == 'string' ? a : this.column_name(a)) > (typeof b == 'string' ? b : this.column_name(b)) ? 1 : -1
+      })
+
       if (SELECT.expand !== 'root') {
         const ret = []
         for (const x of q.SELECT.columns) {
@@ -837,6 +843,33 @@ class HANAService extends SQLService {
       return this.INSERT_entries(q)
     }
 
+    INSERT_select(q) {
+      const { INSERT } = q
+      const entity = this.name(q._target.name, q)
+      const alias = INSERT.into.as
+      const elements = q.elements || q._target?.elements || {}
+      const columns = (INSERT.columns || ObjectKeys(elements)).filter(
+        c => c in elements && !elements[c].virtual && !elements[c].isAssociation,
+      )
+
+      if (columns.length !== INSERT.from.SELECT.columns.length)
+        throw new Error('The number of specified columns does not match the number of selected columns')
+      this.columns = []
+      INSERT.from.SELECT.columns = INSERT.from.SELECT.columns
+        .map((col, originalIdx) => [typeof col == 'string' ? col : this.column_name(col), originalIdx])
+        .sort(([colNameA], [colNameB]) => colNameA > colNameB ? 1 : -1)
+        .map(([, originalIdx], i) => {
+          this.columns[i] = columns[originalIdx]
+          return INSERT.from.SELECT.columns[originalIdx]
+        })
+
+      this.sql = `INSERT INTO ${this.quote(entity)}${alias ? ' as ' + this.quote(alias) : ''} (${this.columns.map(c =>
+        this.quote(c),
+      )}) ${this.SELECT(this.cqn4sql(INSERT.from || INSERT.as))}`
+      this.entries = [this.values]
+      return this.sql
+    }
+
     UPSERT(q) {
       const { UPSERT } = q
       // REVISIT: should @cds.persistence.name be considered ?

hana/test/column-order.test.js

@@ -0,0 +1,123 @@
+const cds = require('../../test/cds.js')
+const bookshop = cds.utils.path.resolve(__dirname, '../../test/bookshop')
+
+describe('column order', () => {
+  const { expect } = cds.test(bookshop)
+
+  describe('regardless of column order specifed in query', () => {
+    let hanaService
+
+    beforeAll(async () => {
+      hanaService = await cds.connect.to('db')
+    })
+
+    const expectSqlScriptToBeEqual = (query1, query2) => {
+      const sql1 = hanaService.cqn2sql(query1)
+      const sql2 = hanaService.cqn2sql(query2)
+      expect(sql1.sql).to.equal(sql2.sql)
+
+      const sqlScript1 = hanaService.wrapTemporary(sql1.temporary, sql1.withclause, sql1.blobs)
+      const sqlScript2 = hanaService.wrapTemporary(sql2.temporary, sql2.withclause, sql2.blobs)
+      expect(sqlScript1).to.equal(sqlScript2)
+    }
+
+    test('should select columns in the same order', async () => {
+      const query1 = SELECT.from('sap.capire.bookshop.Books').columns(['ID', 'title', 'descr', 'stock', 'price'])
+      const query2 = SELECT.from('sap.capire.bookshop.Books').columns(['stock', 'title', 'price', 'ID', 'descr'])
+
+      expectSqlScriptToBeEqual(query1, query2)
+    })
+
+    test('should select expands in the same order', async () => {
+      const query1 = SELECT.from('sap.capire.bookshop.Books').columns([
+        { ref: ['author'], expand: [{ ref: ['name'] }] },
+        { ref: ['genre'], expand: [{ ref: ['ID'] }] },
+      ])
+      const query2 = SELECT.from('sap.capire.bookshop.Books').columns([
+        { ref: ['genre'], expand: [{ ref: ['ID'] }] },
+        { ref: ['author'], expand: [{ ref: ['name'] }] },
+      ])
+
+      expectSqlScriptToBeEqual(query1, query2)
+    })
+
+    test('should select flat expands in the same order', async () => {
+      const query1 = SELECT.from('sap.capire.bookshop.Books').columns([
+        'ID',
+        { ref: ['author', 'ID'] },
+        { ref: ['genre', 'ID'] },
+        { ref: ['author', 'name'] },
+      ])
+      const query2 = SELECT.from('sap.capire.bookshop.Books').columns([
+        { ref: ['genre', 'ID'] },
+        { ref: ['author', 'name'] },
+        { ref: ['author', 'ID'] },
+        'ID',
+      ])
+
+      expectSqlScriptToBeEqual(query1, query2)
+    })
+
+    test('should select columns and expands in the same order', async () => {
+      const query1 = SELECT.from('sap.capire.bookshop.Books').columns([
+        'ID',
+        { ref: ['author'], expand: [{ ref: ['ID'] }, { ref: ['name'] }] },
+        { ref: ['genre', 'ID'] },
+      ])
+      const query2 = SELECT.from('sap.capire.bookshop.Books').columns([
+        { ref: ['genre', 'ID'] },
+        { ref: ['author'], expand: [{ ref: ['ID'] }, { ref: ['name'] }] },
+        'ID',
+      ])
+
+      expectSqlScriptToBeEqual(query1, query2)
+    })
+
+    test('should select columns from expands in the same order', async () => {
+      const query1 = SELECT.from('sap.capire.bookshop.Books').columns([
+        'ID',
+        { ref: ['author'], expand: [{ ref: ['ID'] }, { ref: ['name'] }] },
+      ])
+      const query2 = SELECT.from('sap.capire.bookshop.Books').columns([
+        { ref: ['author'], expand: [{ ref: ['name'] }, { ref: ['ID'] }] },
+        'ID',
+      ])
+
+      expectSqlScriptToBeEqual(query1, query2)
+    })
+
+    test('should select functions in the same order', async () => {
+      const query1 = SELECT.from('sap.capire.bookshop.Books').columns(['ID', { xpr: ['1=1'], as: 'always_true' }])
+      const query2 = SELECT.from('sap.capire.bookshop.Books').columns([{ xpr: ['1=1'], as: 'always_true' }, 'ID'])
+
+      expectSqlScriptToBeEqual(query1, query2)
+    })
+
+    test('should select expressions in the same order', async () => {
+      const query1 = SELECT.from('sap.capire.bookshop.Books').columns([
+        'ID',
+        { func: 'max', args: [{ ref: ['price'] }] },
+      ])
+      const query2 = SELECT.from('sap.capire.bookshop.Books').columns([
+        { func: 'max', args: [{ ref: ['price'] }] },
+        'ID',
+      ])
+
+      expectSqlScriptToBeEqual(query1, query2)
+    })
+
+    test('should select values in the same order', async () => {
+      const query1 = SELECT.from('sap.capire.bookshop.Books').columns(['ID', { val: 'some-static-value' }])
+      const query2 = SELECT.from('sap.capire.bookshop.Books').columns([{ val: 'some-static-value' }, 'ID'])
+
+      expectSqlScriptToBeEqual(query1, query2)
+    })
+
+    test('should select numeric values in the same order', async () => {
+      const query1 = SELECT.from('sap.capire.bookshop.Books').columns(['ID', { val: 1 }])
+      const query2 = SELECT.from('sap.capire.bookshop.Books').columns([{ val: 1 }, 'ID'])
+
+      expectSqlScriptToBeEqual(query1, query2)
+    })
+  })
+})