jtdsdatabasemetadata.java

第三方的SQL Server and Sybase的jdbc dirver,速度更快

        rsTmp.moveToInsertRow();
        while (rs.next()) {
            for (int i = 1; i <= colCnt; i++) {
                rsTmp.updateObject(i, rs.getObject(i));
            }
            rsTmp.insertRow();
        }
        rs.close();
        rsTmp.moveToCurrentRow();
        rsTmp.setConcurrency(ResultSet.CONCUR_READ_ONLY);

        return rsTmp;
    }

    //----------------------------------------------------------------------
    // The following group of methods exposes various limitations
    // based on the target database with the current driver.
    // Unless otherwise specified, a result of zero means there is no
    // limit, or the limit is not known.

    /**
     * How many hex characters can you have in an inline binary literal?
     *
     * @return max literal length
     * @throws SQLException if a database-access error occurs.
     */
    public int getMaxBinaryLiteralLength() throws SQLException {
        // Sybase jConnect says 255
        // Actual value is 16384 for Sybase 12.5
        // MS JDBC says 0
        // Probable maximum size for MS is 65,536 * network packet size
        return 131072;
        // per "Programming ODBC for SQLServer" Appendix A
    }

    /**
     * What's the maximum length of a catalog name?
     *
     * @return max name length in bytes
     * @throws SQLException if a database-access error occurs.
     */
    public int getMaxCatalogNameLength() throws SQLException {
        return sysnameLength;
    }

    /**
     * What's the max length for a character literal?
     *
     * @return max literal length
     * @throws SQLException if a database-access error occurs.
     */
    public int getMaxCharLiteralLength() throws SQLException {
        // Sybase jConnect says 255
        // Actual value is 16384 for Sybase 12.5
        // MS JDBC says 0
        // Probable maximum size for MS is 65,536 * network packet size
        return 131072;
        // per "Programming ODBC for SQLServer" Appendix A
    }

    /**
     * What's the limit on column name length?
     *
     * @return max literal length
     * @throws SQLException if a database-access error occurs.
     */
    public int getMaxColumnNameLength() throws SQLException {
        // per "Programming ODBC for SQLServer" Appendix A
        return sysnameLength;
    }

    /**
     * What's the maximum number of columns in a "GROUP BY" clause?
     *
     * @return max number of columns
     * @throws SQLException if a database-access error occurs.
     */
    public int getMaxColumnsInGroupBy() throws SQLException {
        // Sybase jConnect says 16
        // MS JDBC says 16
        // per "Programming ODBC for SQLServer" Appendix A
        // Actual MS value is 8060 / average bytes per column
        return (tdsVersion >= Driver.TDS70) ? 0 : 16;
    }

    /**
     * What's the maximum number of columns allowed in an index?
     *
     * @return max columns
     * @throws SQLException if a database-access error occurs.
     */
    public int getMaxColumnsInIndex() throws SQLException {
        // per SQL Server Books Online "Administrator's Companion",
        // Part 1, Chapter 1.
        // Sybase 12.5 is 31
        return 16;
    }

    /**
     * What's the maximum number of columns in an "ORDER BY" clause?
     *
     * @return max columns
     * @throws SQLException if a database-access error occurs.
     */
    public int getMaxColumnsInOrderBy() throws SQLException {
        // per "Programming ODBC for SQLServer" Appendix A
        // Sybase 12.5 is 31
        // Actual MS value is 8060 / average bytes per column
        return (tdsVersion >= Driver.TDS70) ? 0 : 16;
    }

    /**
     * What's the maximum number of columns in a "SELECT" list?
     *
     * @return max columns
     * @throws SQLException if a database-access error occurs.
     */
    public int getMaxColumnsInSelect() throws SQLException {
        // Sybase jConnect says 0
        // per "Programming ODBC for SQLServer" Appendix A
        return 4096;
    }

    /**
     * What's the maximum number of columns in a table?
     *
     * @return max columns
     * @throws SQLException if a database-access error occurs.
     */
    public int getMaxColumnsInTable() throws SQLException {
        // Sybase jConnect says 250
        // per "Programming ODBC for SQLServer" Appendix A
        // MS 2000 should be 4096
        // Sybase 12.5 is now 1024
        return (tdsVersion >= Driver.TDS70) ? 1024 : 250;
    }

    /**
     * How many active connections can we have at a time to this database?
     *
     * @return max connections
     * @throws SQLException if a database-access error occurs.
     */
    public int getMaxConnections() throws SQLException {
        // Sybase - could query syscurconfigs to get actual value
        // which in practice will be a lot less than 32767!
        // per SQL Server Books Online "Administrator's Companion",
        // Part 1, Chapter 1.
        return 32767;
    }

    /**
     * What's the maximum cursor name length?
     *
     * @return max cursor name length in bytes
     * @throws SQLException if a database-access error occurs.
     */
    public int getMaxCursorNameLength() throws SQLException {
        // per "Programming ODBC for SQLServer" Appendix A
        return sysnameLength;
    }

    /**
     * What's the maximum length of an index (in bytes)?
     *
     * @return max index length in bytes
     * @throws SQLException if a database-access error occurs.
     */
    public int getMaxIndexLength() throws SQLException {
        // Sybase JConnect says 255
        // Actual Sybase 12.5 is 600 - 5300 depending on page size
        // per "Programming ODBC for SQLServer" Appendix A
        return (tdsVersion >= Driver.TDS70) ? 900 : 255;
    }

    /**
     * What's the maximum length of a procedure name?
     *
     * @return max name length in bytes
     * @throws SQLException if a database-access error occurs.
     */
    public int getMaxProcedureNameLength() throws SQLException {
        // per "Programming ODBC for SQLServer" Appendix A
        return sysnameLength;
    }

    /**
     * What's the maximum length of a single row?
     *
     * @return max row size in bytes
     * @throws SQLException if a database-access error occurs.
     */
    public int getMaxRowSize() throws SQLException {
        // Sybase jConnect says 1962 but this can be more with wide tables.
        // per SQL Server Books Online "Administrator's Companion",
        // Part 1, Chapter 1.
        return (tdsVersion >= Driver.TDS70) ? 8060 : 1962;
    }

    /**
     * What's the maximum length allowed for a schema name?
     *
     * @return max name length in bytes
     * @throws SQLException if a database-access error occurs.
     */
    public int getMaxSchemaNameLength() throws SQLException {
        return sysnameLength;
    }

    /**
     * What's the maximum length of a SQL statement?
     *
     * @return max length in bytes
     * @throws SQLException if a database-access error occurs.
     */
    public int getMaxStatementLength() throws SQLException {
        // I think this should return 0 (no limit)
        // actual limit for SQL 7/2000 is 65536 * packet size!
        // Sybase JConnect says 0
        // MS JDBC says 0
        // per "Programming ODBC for SQLServer" Appendix A
        return 0;
    }

    /**
     * How many active statements can we have open at one time to this
     * database?
     *
     * @return the maximum
     * @throws SQLException if a database-access error occurs.
     */
    public int getMaxStatements() throws SQLException {
        return 0;
    }

    /**
     * What's the maximum length of a table name?
     *
     * @return max name length in bytes
     * @throws SQLException if a database-access error occurs.
     */
    public int getMaxTableNameLength() throws SQLException {
        // per "Programming ODBC for SQLServer" Appendix A
        return sysnameLength;
    }

    /**
     * What's the maximum number of tables in a SELECT?
     *
     * @return the maximum
     * @throws SQLException if a database-access error occurs.
     */
    public int getMaxTablesInSelect() throws SQLException {
        // Sybase JConnect says 256
        // MS JDBC says 32!
        // Actual Sybase 12.5 is 50
        // per "Programming ODBC for SQLServer" Appendix A
        return (tdsVersion > Driver.TDS50) ? 256 : 16;
    }

    /**
     *   What's the maximum length of a user name?
     *
     * @return max name length in bytes
     * @throws SQLException if a database-access error occurs.
     */
    public int getMaxUserNameLength() throws SQLException {
        return sysnameLength;
    }

    /**
     * Get a comma separated list of math functions.
     *
     * @return the list
     * @throws SQLException if a database-access error occurs.
     */
    public String getNumericFunctions() throws SQLException {
        // I don't think either Sybase or SQL have a truncate maths function
        // so I have removed it from the list.
        // Also all other drivers return this list in lower case. Should we?
        return "abs,acos,asin,atan,atan2,ceiling,cos,cot,degrees,exp,floor,log,"
            + "log10,mod,pi,power,radians,rand,round,sign,sin,sqrt,tan";
    }

    /**
     * Get a description of a table's primary key columns. They are ordered by
     * COLUMN_NAME. <P>
     *
     * Each primary key column description has the following columns:
     * <OL>
     *   <LI> <B>TABLE_CAT</B> String =>table catalog (may be null)
     *   <LI> <B>TABLE_SCHEM</B> String =>table schema (may be null)
     *   <LI> <B>TABLE_NAME</B> String =>table name
     *   <LI> <B>COLUMN_NAME</B> String =>column name
     *   <LI> <B>KEY_SEQ</B> short =>sequence number within primary key
     *   <LI> <B>PK_NAME</B> String =>primary key name (may be null)
     * </OL>
     *
     * @param catalog a catalog name; "" retrieves those without a
     *        <code>null</code> means drop catalog name from the selection criteria
     * @param schema a schema name; "" retrieves those without a schema
     * @param table a table name
     * @return ResultSet - each row is a primary key column description
     * @throws SQLException if a database-access error occurs.
     */
    public java.sql.ResultSet getPrimaryKeys(String catalog,
                                             String schema,
                                             String table)
    throws SQLException {
        String colNames[] = {"TABLE_CAT",    "TABLE_SCHEM",
                             "TABLE_NAME",   "COLUMN_NAME",
                             "KEY_SEQ",      "PK_NAME"};
        int    colTypes[] = {Types.VARCHAR,  Types.VARCHAR,
                             Types.VARCHAR,  Types.VARCHAR,
                             Types.SMALLINT, Types.VARCHAR};
        String query = "sp_pkeys ?, ?, ?";

        CallableStatement s = connection.prepareCall(syscall(catalog, query));

        s.setString(1, table);