change

src/connector/jdbc/src/main/java/com/taosdata/jdbc/TSDBDatabaseMetaData.java

@@ -616,7 +616,6 @@ public class TSDBDatabaseMetaData implements java.sql.DatabaseMetaData {
             columnMetaDataList.add(col10);
             resultSet.setColumnMetaDataList(columnMetaDataList);
 
-
             List<TSDBResultSetRowData> rowDataList = new ArrayList<>();
             ResultSet tables = stmt.executeQuery("show tables");
             while (tables.next()) {
@@ -655,8 +654,10 @@ public class TSDBDatabaseMetaData implements java.sql.DatabaseMetaData {
     }
 
     public ResultSet getTableTypes() throws SQLException {
-        DatabaseMetaDataResultSet resultSet = new DatabaseMetaDataResultSet();
+        if (conn == null || conn.isClosed())
+            throw new SQLException(TSDBConstants.FixErrMsg(TSDBConstants.JNI_CONNECTION_NULL));
 
+        DatabaseMetaDataResultSet resultSet = new DatabaseMetaDataResultSet();
         // set up ColumnMetaDataList
         List<ColumnMetaData> columnMetaDataList = new ArrayList<>(1);
         ColumnMetaData colMetaData = new ColumnMetaData();
@@ -681,91 +682,113 @@ public class TSDBDatabaseMetaData implements java.sql.DatabaseMetaData {
     }
 
     public ResultSet getColumns(String catalog, String schemaPattern, String tableNamePattern, String columnNamePattern) throws SQLException {
-        // add by zyyang-taosdata
-        Statement stmt;
-        if (null != conn && !conn.isClosed()) {
-            stmt = conn.createStatement();
+        if (conn == null || conn.isClosed())
+            throw new SQLException(TSDBConstants.FixErrMsg(TSDBConstants.JNI_CONNECTION_NULL));
+
+        try (Statement stmt = conn.createStatement()) {
             if (catalog == null || catalog.isEmpty())
                 return null;
 
-            stmt.executeUpdate("use " + catalog);
+            ResultSet databases = stmt.executeQuery("show databases");
+            String dbname = null;
+            while (databases.next()) {
+                dbname = databases.getString("name");
+                if (dbname.equalsIgnoreCase(catalog))
+                    break;
+            }
+            databases.close();
+            if (dbname == null)
+                return null;
+
+            stmt.execute("use " + dbname);
             DatabaseMetaDataResultSet resultSet = new DatabaseMetaDataResultSet();
             // set up ColumnMetaDataList
             List<ColumnMetaData> columnMetaDataList = new ArrayList<>(24);
+            // TABLE_CAT
+            ColumnMetaData col1 = new ColumnMetaData();
+            col1.setColIndex(1);
+            col1.setColName("TABLE_CAT");
+            col1.setColType(TSDBConstants.TSDB_DATA_TYPE_NCHAR);
+            columnMetaDataList.add(col1);
+            // TABLE_SCHEM
+            ColumnMetaData col2 = new ColumnMetaData();
+            col2.setColIndex(2);
+            col2.setColName("TABLE_SCHEM");
+            col2.setColType(TSDBConstants.TSDB_DATA_TYPE_NCHAR);
+            columnMetaDataList.add(col2);
+            // TABLE_NAME
+            ColumnMetaData col3 = new ColumnMetaData();
+            col3.setColIndex(3);
+            col3.setColName("TABLE_NAME");
+            col3.setColSize(193);
+            col3.setColType(TSDBConstants.TSDB_DATA_TYPE_NCHAR);
+            columnMetaDataList.add(col3);
+            // COLUMN_NAME
+            ColumnMetaData col4 = new ColumnMetaData();
+            col4.setColIndex(4);
+            col4.setColName("COLUMN_NAME");
+            col4.setColSize(65);
+            col4.setColType(TSDBConstants.TSDB_DATA_TYPE_NCHAR);
+            columnMetaDataList.add(col4);
+            // DATA_TYPE
+            ColumnMetaData col5 = new ColumnMetaData();
+            col5.setColIndex(5);
+            col5.setColName("DATA_TYPE");
+            col5.setColType(TSDBConstants.TSDB_DATA_TYPE_INT);
+            columnMetaDataList.add(col5);
+            // TYPE_NAME
+            ColumnMetaData col6 = new ColumnMetaData();
+            col6.setColIndex(6);
+            col6.setColName("TYPE_NAME");
+            col6.setColType(TSDBConstants.TSDB_DATA_TYPE_NCHAR);
+            columnMetaDataList.add(col6);
+            // COLUMN_SIZE
+            ColumnMetaData col7 = new ColumnMetaData();
+            col7.setColIndex(7);
+            col7.setColName("COLUMN_SIZE");
+            col7.setColType(TSDBConstants.TSDB_DATA_TYPE_INT);
+            columnMetaDataList.add(col7);
+            // BUFFER_LENGTH ,not used
             columnMetaDataList.add(null);
-            columnMetaDataList.add(null);
-            // add TABLE_NAME
-            ColumnMetaData colMetaData = new ColumnMetaData();
-            colMetaData.setColIndex(3);
-            colMetaData.setColName("TABLE_NAME");
-            colMetaData.setColSize(193);
-            colMetaData.setColType(TSDBConstants.TSDB_DATA_TYPE_BINARY);
-            columnMetaDataList.add(colMetaData);
-            // add COLUMN_NAME
-            colMetaData = new ColumnMetaData();
-            colMetaData.setColIndex(4);
-            colMetaData.setColName("COLUMN_NAME");
-            colMetaData.setColSize(65);
-            colMetaData.setColType(TSDBConstants.TSDB_DATA_TYPE_BINARY);
-            columnMetaDataList.add(colMetaData);
-            // add DATA_TYPE
-            colMetaData = new ColumnMetaData();
-            colMetaData.setColIndex(5);
-            colMetaData.setColName("DATA_TYPE");
-            colMetaData.setColType(TSDBConstants.TSDB_DATA_TYPE_INT);
-            columnMetaDataList.add(colMetaData);
-            // add TYPE_NAME
-            colMetaData = new ColumnMetaData();
-            colMetaData.setColIndex(6);
-            colMetaData.setColName("TYPE_NAME");
-            colMetaData.setColType(TSDBConstants.TSDB_DATA_TYPE_BINARY);
-            columnMetaDataList.add(colMetaData);
-            // add COLUMN_SIZE
-            colMetaData = new ColumnMetaData();
-            colMetaData.setColIndex(7);
-            colMetaData.setColName("COLUMN_SIZE");
-            colMetaData.setColType(TSDBConstants.TSDB_DATA_TYPE_INT);
-            columnMetaDataList.add(colMetaData);
-            // add BUFFER_LENGTH ,not used
-            columnMetaDataList.add(null);
-            // add DECIMAL_DIGITS
-            colMetaData = new ColumnMetaData();
-            colMetaData.setColIndex(9);
-            colMetaData.setColName("DECIMAL_DIGITS");
-            colMetaData.setColType(TSDBConstants.TSDB_DATA_TYPE_INT);
-            columnMetaDataList.add(colMetaData);
+            // DECIMAL_DIGITS
+            ColumnMetaData col9 = new ColumnMetaData();
+            col9.setColIndex(9);
+            col9.setColName("DECIMAL_DIGITS");
+            col9.setColType(TSDBConstants.TSDB_DATA_TYPE_INT);
+            columnMetaDataList.add(col9);
             // add NUM_PREC_RADIX
-            colMetaData = new ColumnMetaData();
-            colMetaData.setColIndex(10);
-            colMetaData.setColName("NUM_PREC_RADIX");
-            colMetaData.setColType(TSDBConstants.TSDB_DATA_TYPE_INT);
-            columnMetaDataList.add(colMetaData);
-            // add NULLABLE
-            colMetaData = new ColumnMetaData();
-            colMetaData.setColIndex(11);
-            colMetaData.setColName("NULLABLE");
-            colMetaData.setColType(TSDBConstants.TSDB_DATA_TYPE_INT);
-            columnMetaDataList.add(colMetaData);
-
+            ColumnMetaData col10 = new ColumnMetaData();
+            col10.setColIndex(10);
+            col10.setColName("NUM_PREC_RADIX");
+            col10.setColType(TSDBConstants.TSDB_DATA_TYPE_INT);
+            columnMetaDataList.add(col10);
+            // NULLABLE
+            ColumnMetaData col11 = new ColumnMetaData();
+            col11.setColIndex(11);
+            col11.setColName("NULLABLE");
+            col11.setColType(TSDBConstants.TSDB_DATA_TYPE_INT);
+            columnMetaDataList.add(col11);
             resultSet.setColumnMetaDataList(columnMetaDataList);
 
             // set up rowDataList
-            ResultSet resultSet0 = stmt.executeQuery("describe " + tableNamePattern);
+            ResultSet rs = stmt.executeQuery("describe " + dbname + "." + tableNamePattern);
             List<TSDBResultSetRowData> rowDataList = new ArrayList<>();
             int index = 0;
-            while (resultSet0.next()) {
+            while (rs.next()) {
                 TSDBResultSetRowData rowData = new TSDBResultSetRowData(24);
+                // set TABLE_CAT
+                rowData.setString(0, dbname);
                 // set TABLE_NAME
                 rowData.setString(2, tableNamePattern);
                 // set COLUMN_NAME
-                rowData.setString(3, resultSet0.getString(1));
+                rowData.setString(3, rs.getString("Field"));
                 // set DATA_TYPE
-                String typeName = resultSet0.getString(2);
+                String typeName = rs.getString("Type");
                 rowData.setInt(4, getDataType(typeName));
                 // set TYPE_NAME
                 rowData.setString(5, typeName);
                 // set COLUMN_SIZE
-                int length = resultSet0.getInt(3);
+                int length = rs.getInt("Length");
                 rowData.setInt(6, getColumnSize(typeName, length));
                 // set DECIMAL_DIGITS
                 rowData.setInt(8, getDecimalDigits(typeName));
@@ -773,15 +796,18 @@ public class TSDBDatabaseMetaData implements java.sql.DatabaseMetaData {
                 rowData.setInt(9, 10);
                 // set NULLABLE
                 rowData.setInt(10, getNullable(index, typeName));
+                // set REMARKS
+                rowData.setString(11, rs.getString("Note"));
                 rowDataList.add(rowData);
                 index++;
             }
             resultSet.setRowDataList(rowDataList);
-
             return resultSet;
-        } else {
-            throw new SQLException(TSDBConstants.FixErrMsg(TSDBConstants.JNI_CONNECTION_NULL));
+
+        } catch (SQLException e) {
+            e.printStackTrace();
         }
+        return null;
     }
 
     private int getNullable(int index, String typeName) {

src/connector/jdbc/src/test/java/TestTSDBDatabaseMetaData.java

@@ -7,8 +7,8 @@ public class TestTSDBDatabaseMetaData {
 
     public static void main(String[] args) throws SQLException {
         Connection connection = null;
-        DatabaseMetaData dbMetaData = null;
-        ResultSet resSet = null;
+        DatabaseMetaData dbMetaData;
+        ResultSet resSet;
         try {
             Class.forName("com.taosdata.jdbc.TSDBDriver");
             Properties properties = new Properties();

src/connector/jdbc/src/test/java/com/taosdata/jdbc/TSDBDatabaseMetaDataTest.java

@@ -667,7 +667,14 @@ public class TSDBDatabaseMetaDataTest {
 
     @Test
     public void getColumns() throws SQLException {
-        Assert.assertNotNull(metaData.getColumns("", "", "", ""));
+        ResultSet columns = metaData.getColumns("log", "", "dn", "");
+        ResultSetMetaData meta = columns.getMetaData();
+        while (columns.next()) {
+            for (int i = 1; i <= meta.getColumnCount(); i++) {
+                System.out.print(meta.getColumnLabel(i) + ": " + columns.getString(i));
+            }
+            System.out.println();
+        }
     }
 
     @Test