feat: Add simple queries feature flag (#660)

cap-js · May 29, 2024 · 3335202 · 3335202
1 parent 5b07296
commit 3335202
Show file tree

Hide file tree

Showing 2 changed files with 49 additions and 13 deletions.
diff --git a/db-service/lib/cqn2sql.js b/db-service/lib/cqn2sql.js
@@ -257,18 +257,41 @@ class CQN2SQLRenderer {
     const SELECT = q.SELECT
     if (!SELECT.columns) return sql
 
-    let cols = SELECT.columns.map(x => {
-      const name = this.column_name(x)
-      let col = `'$."${name}"',${this.output_converter4(x.element, this.quote(name))}`
-      if (x.SELECT?.count) {
-        // Return both the sub select and the count for @odata.count
-        const qc = cds.ql.clone(x, { columns: [{ func: 'count' }], one: 1, limit: 0, orderBy: 0 })
-        return [col, `'${name}@odata.count',${this.expr(qc)}`]
+    const isRoot = SELECT.expand === 'root'
+    const isSimple = cds.env.features.sql_simple_queries &&
+      isRoot && // Simple queries are only allowed to have a root
+      !ObjectKeys(q.elements).some(e =>
+        q.elements[e].type === 'cds.Boolean' || // REVISIT: Booleans require json for sqlite
+        q.elements[e].isAssociation || // Indicates columns contains an expand
+        q.elements[e].$assocExpand || // REVISIT: sometimes associations are structs
+        q.elements[e].items // Array types require to be inlined with a json result
+      )
+
+    let cols = SELECT.columns.map(isSimple
+      ? x => {
+        const name = this.column_name(x)
+        const escaped = `${name.replace(/"/g, '""')}`
+        let col = `${this.output_converter4(x.element, this.quote(name))} AS "${escaped}"`
+        if (x.SELECT?.count) {
+          // Return both the sub select and the count for @odata.count
+          const qc = cds.ql.clone(x, { columns: [{ func: 'count' }], one: 1, limit: 0, orderBy: 0 })
+          return [col, `${this.expr(qc)} AS "${escaped}@odata.count"`]
+        }
+        return col
       }
-      return col
-    }).flat()
+      : x => {
+        const name = this.column_name(x)
+        const escaped = `${name.replace(/"/g, '""')}`
+        let col = `'$."${escaped}"',${this.output_converter4(x.element, this.quote(name))}`
+        if (x.SELECT?.count) {
+          // Return both the sub select and the count for @odata.count
+          const qc = cds.ql.clone(x, { columns: [{ func: 'count' }], one: 1, limit: 0, orderBy: 0 })
+          return [col, `'$."${escaped}@odata.count"',${this.expr(qc)}`]
+        }
+        return col
+      }).flat()
 
-    const isRoot = SELECT.expand === 'root'
+    if (isSimple) return `SELECT ${cols} FROM (${sql})`
 
     // Prevent SQLite from hitting function argument limit of 100
     let obj = "'{}'"

diff --git a/postgres/lib/PostgresService.js b/postgres/lib/PostgresService.js
@@ -370,7 +370,8 @@ GROUP BY k
       return super.column_alias4(x, q)
     }
 
-    SELECT_expand({ SELECT }, sql) {
+    SELECT_expand(q, sql) {
+      const { SELECT } = q
       if (!SELECT.columns) return sql
       const queryAlias = this.quote(SELECT.from?.as || (SELECT.expand === 'root' && 'root'))
       const cols = SELECT.columns.map(x => {
@@ -385,10 +386,22 @@ GROUP BY k
         }
         return col
       })
+      const isRoot = SELECT.expand === 'root'
+      const isSimple = cds.env.features.sql_simple_queries &&
+        isRoot && // Simple queries are only allowed to have a root
+        !Object.keys(q.elements).some(e =>
+          q.elements[e].isAssociation || // Indicates columns contains an expand
+          q.elements[e].$assocExpand || // REVISIT: sometimes associations are structs
+          q.elements[e].items // Array types require to be inlined with a json result
+        )
+
+      const subQuery = `SELECT ${cols} FROM (${sql}) as ${queryAlias}`
+      if (isSimple) return subQuery
+
       // REVISIT: Remove SELECT ${cols} by adjusting SELECT_columns
       let obj = `to_jsonb(${queryAlias}.*)`
-      return `SELECT ${SELECT.one || SELECT.expand === 'root' ? obj : `coalesce(jsonb_agg (${obj}),'[]'::jsonb)`
-        } as _json_ FROM (SELECT ${cols} FROM (${sql}) as ${queryAlias}) as ${queryAlias}`
+      return `SELECT ${SELECT.one || isRoot ? obj : `coalesce(jsonb_agg (${obj}),'[]'::jsonb)`
+        } as _json_ FROM (${subQuery}) as ${queryAlias}`
     }
 
     doubleQuote(name) {