From 4432bc012fcac045a0b26f3490592794e01b76f3 Mon Sep 17 00:00:00 2001
From: Olav Loite <koloite@gmail.com>
Date: Tue, 8 Dec 2020 19:04:37 +0100
Subject: [PATCH] feat: report whether column is generated in JDBC metadata

Cloud Spanner now supports generated columns. These were reported as normal columns
in the JDBC metadata. These are now reported correctly as generated columns.

Fixes #290
---
 .../jdbc/DatabaseMetaData_GetColumns.sql      |  5 ++-
 .../jdbc/it/ITJdbcDatabaseMetaDataTest.java   | 33 +++++++++++++++++--
 .../spanner/jdbc/it/CreateMusicTables.sql     |  4 ++-
 3 files changed, 37 insertions(+), 5 deletions(-)

diff --git a/src/main/resources/com/google/cloud/spanner/jdbc/DatabaseMetaData_GetColumns.sql b/src/main/resources/com/google/cloud/spanner/jdbc/DatabaseMetaData_GetColumns.sql
index 8b29c15b..69b1f6a8 100644
--- a/src/main/resources/com/google/cloud/spanner/jdbc/DatabaseMetaData_GetColumns.sql
+++ b/src/main/resources/com/google/cloud/spanner/jdbc/DatabaseMetaData_GetColumns.sql
@@ -72,7 +72,10 @@ SELECT TABLE_CATALOG AS TABLE_CAT, TABLE_SCHEMA AS TABLE_SCHEM, TABLE_NAME, COLU
   NULL AS SCOPE_TABLE,
   NULL AS SOURCE_DATA_TYPE,
   'NO' AS IS_AUTOINCREMENT,
-  'NO' AS IS_GENERATEDCOLUMN
+  CASE
+    WHEN (IS_GENERATED = 'NEVER') THEN 'NO'
+    ELSE 'YES'
+  END AS IS_GENERATEDCOLUMN
 FROM INFORMATION_SCHEMA.COLUMNS C
 WHERE UPPER(C.TABLE_CATALOG) LIKE ?
   AND UPPER(C.TABLE_SCHEMA) LIKE ?
diff --git a/src/test/java/com/google/cloud/spanner/jdbc/it/ITJdbcDatabaseMetaDataTest.java b/src/test/java/com/google/cloud/spanner/jdbc/it/ITJdbcDatabaseMetaDataTest.java
index 711363c2..75553998 100644
--- a/src/test/java/com/google/cloud/spanner/jdbc/it/ITJdbcDatabaseMetaDataTest.java
+++ b/src/test/java/com/google/cloud/spanner/jdbc/it/ITJdbcDatabaseMetaDataTest.java
@@ -25,6 +25,7 @@
 
 import com.google.cloud.spanner.IntegrationTest;
 import com.google.cloud.spanner.jdbc.ITAbstractJdbcTest;
+import com.google.cloud.spanner.testing.EmulatorSpannerHelper;
 import java.sql.Connection;
 import java.sql.DatabaseMetaData;
 import java.sql.ResultSet;
@@ -53,7 +54,8 @@ public class ITJdbcDatabaseMetaDataTest extends ITAbstractJdbcTest {
 
   @BeforeClass
   public static void skipOnEmulator() {
-    assumeFalse("foreign keys are not supported on the emulator", env.getTestHelper().isEmulator());
+    assumeFalse(
+        "foreign keys are not supported on the emulator", EmulatorSpannerHelper.isUsingEmulator());
   }
 
   @Override
@@ -70,6 +72,7 @@ private static final class Column {
     private final Integer radix;
     private final boolean nullable;
     private final Integer charOctetLength;
+    private final boolean computed;
 
     private Column(
         String name,
@@ -80,6 +83,19 @@ private Column(
         Integer radix,
         boolean nullable,
         Integer charOctetLength) {
+      this(name, type, typeName, colSize, decimalDigits, radix, nullable, charOctetLength, false);
+    }
+
+    private Column(
+        String name,
+        int type,
+        String typeName,
+        Integer colSize,
+        Integer decimalDigits,
+        Integer radix,
+        boolean nullable,
+        Integer charOctetLength,
+        boolean computed) {
       this.name = name;
       this.type = type;
       this.typeName = typeName;
@@ -88,6 +104,7 @@ private Column(
       this.radix = radix;
       this.nullable = nullable;
       this.charOctetLength = charOctetLength;
+      this.computed = computed;
     }
   }
 
@@ -133,7 +150,17 @@ private Column(
           new Column("ColDateArray", Types.ARRAY, "ARRAY<DATE>", 10, null, null, true, null),
           new Column(
               "ColTimestampArray", Types.ARRAY, "ARRAY<TIMESTAMP>", 35, null, null, true, null),
-          new Column("ColNumericArray", Types.ARRAY, "ARRAY<NUMERIC>", 15, null, 10, true, null));
+          new Column("ColNumericArray", Types.ARRAY, "ARRAY<NUMERIC>", 15, null, 10, true, null),
+          new Column(
+              "ColComputed",
+              Types.NVARCHAR,
+              "STRING(MAX)",
+              2621440,
+              null,
+              null,
+              true,
+              2621440,
+              true));
 
   @Test
   public void testGetColumns() throws SQLException {
@@ -195,7 +222,7 @@ public void testGetColumns() throws SQLException {
           assertThat(rs.getShort("SOURCE_DATA_TYPE"), is(equalTo((short) 0)));
           assertThat(rs.wasNull(), is(true));
           assertThat(rs.getString("IS_AUTOINCREMENT"), is(equalTo("NO")));
-          assertThat(rs.getString("IS_GENERATEDCOLUMN"), is(equalTo("NO")));
+          assertThat(rs.getString("IS_GENERATEDCOLUMN"), is(equalTo(col.computed ? "YES" : "NO")));
           assertThat(rs.getMetaData().getColumnCount(), is(equalTo(24)));
 
           pos++;
diff --git a/src/test/resources/com/google/cloud/spanner/jdbc/it/CreateMusicTables.sql b/src/test/resources/com/google/cloud/spanner/jdbc/it/CreateMusicTables.sql
index 4d05cdfb..6a8c4616 100644
--- a/src/test/resources/com/google/cloud/spanner/jdbc/it/CreateMusicTables.sql
+++ b/src/test/resources/com/google/cloud/spanner/jdbc/it/CreateMusicTables.sql
@@ -84,7 +84,9 @@ CREATE TABLE TableWithAllColumnTypes (
   ColBytesMaxArray	ARRAY<BYTES(MAX)>,
   ColDateArray		ARRAY<DATE>,
   ColTimestampArray	ARRAY<TIMESTAMP>,
-  ColNumericArray	ARRAY<NUMERIC>
+  ColNumericArray	ARRAY<NUMERIC>,
+  
+  ColComputed STRING(MAX) AS (CONCAT(COALESCE(ColString, ''), ' ', COALESCE(ColStringMax, ''))) STORED,
 ) PRIMARY KEY (ColInt64)
 ;