From c023b09d8fd7a7f11677e7a5b4c49754d3d9d75d Mon Sep 17 00:00:00 2001
From: Bob den Os <bob.den.os@sap.com>
Date: Thu, 1 Aug 2024 09:38:20 +0200
Subject: [PATCH 1/2] SQL native FOR JSON alternative

---
 hana/lib/HANAService.js | 30 +++++++++++++++++++++++-------
 1 file changed, 23 insertions(+), 7 deletions(-)

diff --git a/hana/lib/HANAService.js b/hana/lib/HANAService.js
index 0be34a2ce..c73723ed7 100644
--- a/hana/lib/HANAService.js
+++ b/hana/lib/HANAService.js
@@ -15,6 +15,7 @@ const hanaKeywords = keywords.reduce((prev, curr) => {
 
 const DEBUG = cds.debug('sql|db')
 let HANAVERSION = 0
+const JSON_CONCAT = true
 
 /**
  * @implements SQLService
@@ -545,8 +546,16 @@ class HANAService extends SQLService {
                 return false
               }
               if (x.element?.type === 'cds.Boolean') hasBooleans = true
-              const converter = x.element?.[this.class._convertOutput] || (e => e)
-              return `${converter(this.quote(columnName))} as "${columnName.replace(/"/g, '""')}"`
+              let converter = x.element?.[this.class._convertOutput] || src?.elements[columnName]?.[this.class._convertOutput]
+              if (JSON_CONCAT && converter) {
+                const _converter = converter
+                converter = (expr, elem) => `'"' || ${_converter(expr, elem)} || '"'`
+              } else {
+                converter = e => e
+              }
+              return JSON_CONCAT
+                ? `${this.string(JSON.stringify(columnName) + ':')} || coalesce((${converter(this.quote(columnName))}) || '', 'null')`
+                : `${converter(this.quote(columnName))} as "${columnName.replace(/"/g, '""')}"`
             }
             : x => {
               if (x === '*') return '*'
@@ -580,7 +589,10 @@ class HANAService extends SQLService {
         // Making each row a maximum size of 2gb instead of the whole result set to be 2gb
         // Excluding binary columns as they are not supported by FOR JSON and themselves can be 2gb
         const rawJsonColumn = sql.length
-          ? `(SELECT ${sql} FROM JSON_TABLE('[{}]', '$' COLUMNS("'$$FaKeDuMmYCoLuMn$$'" FOR ORDINALITY)) FOR JSON ('format'='no', 'omitnull'='no', 'arraywrap'='no') RETURNS NVARCHAR(2147483647))`
+          ?
+          JSON_CONCAT
+            ? `'{' || ${sql.join(` || ',' || `)} || '}'`
+            : `(SELECT ${sql} FROM JSON_TABLE('[{}]', '$' COLUMNS("'$$FaKeDuMmYCoLuMn$$'" FOR ORDINALITY)) FOR JSON ('format'='no', 'omitnull'='no', 'arraywrap'='no') RETURNS NVARCHAR(2147483647))`
           : `'{}'`
 
         let jsonColumn = rawJsonColumn
@@ -1126,16 +1138,20 @@ class HANAService extends SQLService {
       ...super.OutputConverters,
       // REVISIT: binaries should use BASE64_ENCODE, but this results in BASE64_ENCODE(BINTONHEX(${e}))
       Binary: e => `BINTONHEX(${e})`,
-      Date: e => `to_char(${e}, 'YYYY-MM-DD')`,
-      Time: e => `to_char(${e}, 'HH24:MI:SS')`,
-      DateTime: e => `to_char(${e}, 'YYYY-MM-DD"T"HH24:MI:SS"Z"')`,
-      Timestamp: e => `to_char(${e}, 'YYYY-MM-DD"T"HH24:MI:SS.FF3"Z"')`,
+      Date: e => `TO_NVARCHAR(${e}, 'YYYY-MM-DD')`,
+      Time: e => `TO_NVARCHAR(${e}, 'HH24:MI:SS')`,
+      DateTime: e => `TO_NVARCHAR(${e}, 'YYYY-MM-DD"T"HH24:MI:SS"Z"')`,
+      Timestamp: e => `TO_NVARCHAR(${e}, 'YYYY-MM-DD"T"HH24:MI:SS.FF3"Z"')`,
       Vector: e => `TO_NVARCHAR(${e})`,
       // Reading int64 as string to not loose precision
       Int64: expr => `TO_NVARCHAR(${expr})`,
       // Reading decimal as string to not loose precision
       Decimal: expr => `TO_NVARCHAR(${expr})`,
 
+      String: JSON_CONCAT
+        ? e => `${['\\', '"', '\b', '\t', '\n', '\f', '\r'].reduce((l, c) => `REPLACE(${l},'${c}','${JSON.stringify(c).slice(1, -1)}')`, e)}`
+        : undefined,
+
       // HANA types
       'cds.hana.ST_POINT': e => `(SELECT NEW ST_POINT(TO_NVARCHAR(${e})).ST_X() as "x", NEW ST_POINT(TO_NVARCHAR(${e})).ST_Y() as "y" FROM DUMMY WHERE (${e}) IS NOT NULL FOR JSON ('format'='no', 'omitnull'='no', 'arraywrap'='no') RETURNS NVARCHAR(2147483647))`,
       'cds.hana.ST_GEOMETRY': e => `TO_NVARCHAR(${e})`,

From 7fc5788c8a94a3c7c7fee6fdd1deba52f7ca28c7 Mon Sep 17 00:00:00 2001
From: Bob den Os <bob.den.os@sap.com>
Date: Thu, 1 Aug 2024 09:40:44 +0200
Subject: [PATCH 2/2] Add some more escaped characters tests

---
 .../db/basic/literals/basic.literals.string.js  | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/test/compliance/resources/db/basic/literals/basic.literals.string.js b/test/compliance/resources/db/basic/literals/basic.literals.string.js
index 4de7f9808..b897f83b4 100644
--- a/test/compliance/resources/db/basic/literals/basic.literals.string.js
+++ b/test/compliance/resources/db/basic/literals/basic.literals.string.js
@@ -2,6 +2,8 @@ const alphabet = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
 
 const alphabetize = (_, i) => alphabet[i % alphabet.length]
 
+const bs = String.fromCharCode(92)
+
 module.exports = [
   {
     string: null,
@@ -44,6 +46,21 @@ module.exports = [
     string:
       'Simplified Chinese: 中国, Traditional Chinese: 中國, Korean: 대한민국, Japanese: 日本国, Russion: Российская Федерация, Greek: Ελληνική Δημοκρατία',
   },
+  {
+    string: `${bs}\b\t\n\r"${bs}b${bs}t${bs}n${bs}r${bs}"`,
+  },
+  {
+    string: `${bs}b`,
+  },
+  {
+    string: `${bs}`,
+  },
+  {
+    string: `${bs}${bs}`,
+  },
+  {
+    string: `${bs}\b`,
+  },
   /* Ignoring transformations
   {
     char: () => alphabet,