Merge pull request #659 from findepi/findepi/return-proper-error-when-user-tries-to-enable-transactions-5e522f

Return proper error when user tries to enable transactions

Author: zhicwu

clickhouse-jdbc/src/main/java/ru/yandex/clickhouse/ClickHouseConnectionImpl.java

@@ -209,7 +209,10 @@ public String nativeSQL(String sql) throws SQLException {
 
     @Override
     public void setAutoCommit(boolean autoCommit) throws SQLException {
-
+        if (autoCommit) {
+            return;
+        }
+        throw new SQLFeatureNotSupportedException("Transactions are not supported");
     }
 
     @Override
@@ -219,12 +222,12 @@ public boolean getAutoCommit() throws SQLException {
 
     @Override
     public void commit() throws SQLException {
-
+        throw new SQLException("Cannot commit when auto-commit is enabled");
     }
 
     @Override
     public void rollback() throws SQLException {
-
+        throw new SQLException("Cannot rollback when auto-commit is enabled");
     }
 
     @Override