fix(jdbc): remove support for Statement#getGeneratedKeys

SQLite does not provide a good way to retrieve generated keys in a reliable way

BREAKING-CHANGE: getGeneratedKeys is not supported anymore

Closes: #329

src/main/java/org/sqlite/core/CoreDatabaseMetaData.java

@@ -43,9 +43,6 @@ public abstract class CoreDatabaseMetaData implements DatabaseMetaData {
             getVersionColumns = null,
             getColumnPrivileges = null;
 
-    /** Used to save generating a new statement every call. */
-    protected PreparedStatement getGeneratedKeys = null;
-
     /**
      * Constructor that applies the Connection object.
      *
@@ -55,6 +52,11 @@ protected CoreDatabaseMetaData(SQLiteConnection conn) {
         this.conn = conn;
     }
 
+    /**
+     * @deprecated Not exactly sure what this function does, as it is not implementing any
+     *     interface, and is not used anywhere in the code. Deprecated since 3.43.0.0.
+     */
+    @Deprecated
     public abstract ResultSet getGeneratedKeys() throws SQLException;
 
     /** @throws SQLException */
@@ -122,9 +124,6 @@ public synchronized void close() throws SQLException {
             if (getColumnPrivileges != null) {
                 getColumnPrivileges.close();
             }
-            if (getGeneratedKeys != null) {
-                getGeneratedKeys.close();
-            }
 
             getTables = null;
             getTableTypes = null;
@@ -143,7 +142,6 @@ public synchronized void close() throws SQLException {
             getBestRowIdentifier = null;
             getVersionColumns = null;
             getColumnPrivileges = null;
-            getGeneratedKeys = null;
         } finally {
             conn = null;
         }

src/main/java/org/sqlite/jdbc3/JDBC3DatabaseMetaData.java

@@ -556,7 +556,7 @@ public boolean supportsFullOuterJoins() throws SQLException {
 
     /** @see java.sql.DatabaseMetaData#supportsGetGeneratedKeys() */
     public boolean supportsGetGeneratedKeys() {
-        return true;
+        return false;
     }
 
     /** @see java.sql.DatabaseMetaData#supportsGroupBy() */
@@ -1926,15 +1926,12 @@ public ResultSet getVersionColumns(String c, String s, String t) throws SQLExcep
     }
 
     /**
-     * @return Generated row id of the last INSERT command.
-     * @throws SQLException
+     * @deprecated Not exactly sure what this function does, as it is not implementing any
+     *     interface, and is not used anywhere in the code. Deprecated since 3.43.0.0.
      */
+    @Deprecated
     public ResultSet getGeneratedKeys() throws SQLException {
-        if (getGeneratedKeys == null) {
-            getGeneratedKeys = conn.prepareStatement("select last_insert_rowid();");
-        }
-
-        return getGeneratedKeys.executeQuery();
+        throw new SQLFeatureNotSupportedException("not implemented by SQLite JDBC driver");
     }
 
     /** Not implemented yet. */

src/main/java/org/sqlite/jdbc3/JDBC3Statement.java

@@ -347,13 +347,14 @@ public void setFetchDirection(int direction) throws SQLException {
     }
 
     /**
-     * As SQLite's last_insert_rowid() function is DB-specific not statement specific, this function
-     * introduces a race condition if the same connection is used by two threads and both insert.
+     * SQLite's last_insert_rowid() function is DB-specific, not statement specific, and cannot
+     * provide multiple values when inserting multiple rows. Suggestion is to use a <a
+     * href=https://www.sqlite.org/lang_returning.html>RETURNING</a> clause instead.
      *
      * @see java.sql.Statement#getGeneratedKeys()
      */
     public ResultSet getGeneratedKeys() throws SQLException {
-        return conn.getSQLiteDatabaseMetaData().getGeneratedKeys();
+        throw unsupported();
     }
 
     /**

src/test/java/org/sqlite/DBMetaDataTest.java

@@ -52,7 +52,6 @@ public void getTables() throws SQLException {
         ResultSet rs = meta.getTables(null, null, null, null);
         assertThat(rs).isNotNull();
 
-        stat.getGeneratedKeys().close();
         stat.close();
 
         assertThat(rs.next()).isTrue();

src/test/java/org/sqlite/StatementTest.java

@@ -306,23 +306,9 @@ public void getGeneratedKeys() throws SQLException {
         ResultSet rs;
         stat.executeUpdate("create table t1 (c1 integer primary key, v);");
         stat.executeUpdate("insert into t1 (v) values ('red');");
-        rs = stat.getGeneratedKeys();
-        assertThat(rs.next()).isTrue();
-        assertThat(rs.getInt(1)).isEqualTo(1);
-        rs.close();
-        stat.executeUpdate("insert into t1 (v) values ('blue');");
-        rs = stat.getGeneratedKeys();
-        assertThat(rs.next()).isTrue();
-        assertThat(rs.getInt(1)).isEqualTo(2);
-        rs.close();
 
-        // closing one statement shouldn't close shared db metadata object.
-        stat.close();
-        Statement stat2 = conn.createStatement();
-        rs = stat2.getGeneratedKeys();
-        assertThat(rs).isNotNull();
-        rs.close();
-        stat2.close();
+        assertThatExceptionOfType(SQLFeatureNotSupportedException.class)
+                .isThrownBy(() -> stat.getGeneratedKeys());
     }
 
     @Test