microsoft7metadata.java

Java写的TDS协议(JDBC/ODBC)实现

//
// Copyright 1998 CDS Networks, Inc., Medford Oregon
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package net.sourceforge.jtds.jdbc;



import java.sql.*;


public class Microsoft7MetaData extends DatabaseMetaData
{
   public static final String cvsVersion = "$Id: Microsoft7MetaData.java,v 1.1 2002/10/14 10:48:59 alin_sinpalean Exp $";


   protected Microsoft7MetaData(
      TdsConnection connection_,
      Tds           tds_) throws SQLException
   {
      super(connection_, tds_);
      sysnameLength = 128;
   }


   /**
    * What's the maximum number of columns in a "GROUP BY" clause?
    *
    * @return max number of columns
    * @exception SQLException if a database-access error occurs.
    */
   public int getMaxColumnsInGroupBy() throws SQLException
   {
      // Limited only by the number of bytes
      return 0; // per "SQL Server Books Online" Maximum Capacity Specifications
   }


   /**
    * What's the maximum number of columns in an "ORDER BY" clause?
    *
    * @return max columns
    * @exception SQLException if a database-access error occurs.
    */
   public int getMaxColumnsInOrderBy() throws SQLException
   {
      // Limited only by the number of bytes
      return 0; // per "SQL Server Books Online" Maximum Capacity Specifications
   }


   /**
    * What's the maximum number of columns in a table?
    *
    * @return max columns
    * @exception SQLException if a database-access error occurs.
    */
   public int getMaxColumnsInTable() throws SQLException
   {
      // XXX How do we find this out for Sybase?
      return 1024; // per "SQL Server Books Online" Maximum Capacity Specifications
   }


   /**
    * What's the maximum length of a single row?
    *
    * @return max row size in bytes
    * @exception SQLException if a database-access error occurs.
    */
   public int getMaxRowSize() throws SQLException
   {
      return 8060; // per "SQL Server Books Online" Maximum Capacity Specifications
   }


   /**
    * What's the maximum number of tables in a SELECT?
    *
    * @return the maximum
    * @exception SQLException if a database-access error occurs.
    */
   public int getMaxTablesInSelect() throws SQLException
   {
      return 256; // per "SQL Server Books Online" Maximum Capacity Specifications
   }


   /**
    * Is "ALTER TABLE" with drop column supported?
    *
    * @return true if so
    * @exception SQLException if a database-access error occurs.
    */
   public boolean supportsAlterTableWithDropColumn() throws SQLException
   {
      return true;
   }
}