fix: return null when SELECT.one returns empty result instead of empt…

…y array (#266)

__tests__/lib/pg/ql.test.js

@@ -5,7 +5,7 @@ const deploy = require('@sap/cds/lib/deploy')
 cds.env.requires.db = { kind: 'postgres' }
 cds.env.requires.postgres = {
  dialect: 'plain',
- impl: './cds-pg', // hint: not really sure as to why this is, but...
+ impl: './cds-pg' // hint: not really sure as to why this is, but...
 }
 
 jest.setTimeout(100000)
@@ -22,8 +22,8 @@ describe('QL to PostgreSQL', () => {
  port: '5432',
  database: 'beershop',
  username: 'postgres',
- password: 'postgres',
- },
+ password: 'postgres'
+ }
  }
  cds.db = await cds.connect.to(this._dbProperties)
  })
@@ -61,6 +61,13 @@ describe('QL to PostgreSQL', () => {
  expect(beer).not.toHaveProperty('abv')
  })
 
+ test('-> with one - no result returns null not empty array', async () => {
+ const { Beers } = cds.entities('csw')
+ const beer = await cds.run(SELECT.one(Beers).where({ name: 'does not exist' }))
+ expect(beer).not.toBeInstanceOf(Array)
+ expect(beer).toBeNull()
+ })
+
  test.todo('-> with distinct')
  test.todo('-> with orderBy')
  test.todo('-> with groupBy')

lib/pg/execute.js

@@ -96,7 +96,7 @@ const executeInsertCQN = async (model, dbc, cqn, user) => {
 async function executePlainSQL(dbc, rawSql, rawValues) {
  const { sql, values } = _replacePlaceholders({
  sql: rawSql,
- values: rawValues,
+ values: rawValues
  })
 
  DEBUG && DEBUG('sql > ', sql)
@@ -149,11 +149,11 @@ function _cqnToSQL(model, cqn, user, isExpand = false) {
  SelectBuilder: PGSelectBuilder,
  ResourceBuilder: PGResourceBuilder,
  ExpressionBuilder: PGExpressionBuilder,
- FunctionBuilder: PGFunctionBuilder,
+ FunctionBuilder: PGFunctionBuilder
  },
  isExpand, // Passed to inform the select builder that we are dealing with an expand call
  now: 'NOW ()',
- user,
+ user
  },
  model,
  isExpand
@@ -210,7 +210,14 @@ async function _executeSQLReturningRows(dbc, sql, values, isOne, postMapper, pro
  DEBUG && values && values.length > 0 && DEBUG('values > ', values)
 
  let rawResult = await dbc.query(sql, values)
- const result = isOne && rawResult.rows.length > 0 ? rawResult.rows[0] : rawResult.rows
+ let result
+ if (isOne && rawResult.rows.length > 0) {
+ result = rawResult.rows[0]
+ } else if (isOne && rawResult.rows.length === 0) {
+ result = null
+ } else {
+ result = rawResult.rows
+ }
  return postProcess(result, postMapper, propertyMapper, objStructMapper)
 }
 
@@ -226,5 +233,5 @@ module.exports = {
  read: executeSelectCQN,
  //stream: executeSelectStreamCQN,
  cqn: executeGenericCQN,
- sql: executePlainSQL,
+ sql: executePlainSQL
 }