fix: call .next() before getting metadata

googleapis · Mar 10, 2021 · e591b57 · e591b57
1 parent b3cdced
commit e591b57
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Showing 2 changed files with 15 additions and 2 deletions.
diff --git a/src/main/java/com/google/cloud/spanner/jdbc/JdbcPreparedStatement.java b/src/main/java/com/google/cloud/spanner/jdbc/JdbcPreparedStatement.java
@@ -99,8 +99,10 @@ public ResultSetMetaData getMetaData() throws SQLException {
     if (StatementParser.INSTANCE.isUpdateStatement(sql)) {
       // Return metadata for an empty result set as DML statements do not return any results (as a
       // result set).
-      return new JdbcResultSetMetaData(
-          JdbcResultSet.of(ResultSets.forRows(Type.struct(), ImmutableList.<Struct>of())), this);
+      com.google.cloud.spanner.ResultSet resultSet =
+          ResultSets.forRows(Type.struct(), ImmutableList.<Struct>of());
+      resultSet.next();
+      return new JdbcResultSetMetaData(JdbcResultSet.of(resultSet), this);
     }
     try (ResultSet rs = analyzeQuery(createStatement(), QueryAnalyzeMode.PLAN)) {
       return rs.getMetaData();

diff --git a/src/test/java/com/google/cloud/spanner/jdbc/JdbcPreparedStatementTest.java b/src/test/java/com/google/cloud/spanner/jdbc/JdbcPreparedStatementTest.java
@@ -307,4 +307,15 @@ public void testGetResultSetMetadata() throws SQLException {
       assertEquals(Types.DOUBLE, metadata.getColumnType(3));
     }
   }
+
+  @Test
+  public void testGetResultSetMetaDataForDml() throws SQLException {
+    Connection connection = mock(Connection.class);
+    try (JdbcPreparedStatement ps =
+        new JdbcPreparedStatement(
+            createMockConnection(connection), "UPDATE FOO SET BAR=1 WHERE TRUE")) {
+      ResultSetMetaData metadata = ps.getMetaData();
+      assertEquals(0, metadata.getColumnCount());
+    }
+  }
 }