databasemetadata.java

一个JDBC数据库连接的组件

     *
     * @param catalog a catalog name; "" retrieves those without a
     * catalog; null means drop catalog name from the selection criteria
     * @param schema a schema name; "" retrieves those without a schema
     * @param table a table name
     * @param scope the scope of interest; use same values as SCOPE
     * @param nullable include columns that are nullable?
     * @return ResultSet - each row is a column description 
     * @exception SQLException if a database-access error occurs.
     */
	ResultSet getBestRowIdentifier(String catalog, String schema,
		String table, int scope, boolean nullable) throws SQLException;
	
    /**
     * BEST ROW SCOPE - very temporary, while using row.
     */
	int bestRowTemporary   = 0;

    /**
     * BEST ROW SCOPE - valid for remainder of current transaction.
     */
	int bestRowTransaction = 1;

    /**
     * BEST ROW SCOPE - valid for remainder of current session.
     */
	int bestRowSession     = 2;

    /**
     * BEST ROW PSEUDO_COLUMN - may or may not be pseudo column.
     */
	int bestRowUnknown	= 0;

    /**
     * BEST ROW PSEUDO_COLUMN - is NOT a pseudo column.
     */
	int bestRowNotPseudo	= 1;

    /**
     * BEST ROW PSEUDO_COLUMN - is a pseudo column.
     */
	int bestRowPseudo	= 2;

    /**
     * Get a description of a table's columns that are automatically
     * updated when any value in a row is updated.  They are
     * unordered.
     *
     * <P>Each column description has the following columns:
     *  <OL>
     *	<LI><B>SCOPE</B> short => is not used
     *	<LI><B>COLUMN_NAME</B> String => column name
     *	<LI><B>DATA_TYPE</B> short => SQL data type from java.sql.Types
     *	<LI><B>TYPE_NAME</B> String => Data source dependent type name
     *	<LI><B>COLUMN_SIZE</B> int => precision
     *	<LI><B>BUFFER_LENGTH</B> int => length of column value in bytes
     *	<LI><B>DECIMAL_DIGITS</B> short	 => scale
     *	<LI><B>PSEUDO_COLUMN</B> short => is this a pseudo column 
     *      like an Oracle ROWID
     *      <UL>
     *      <LI> versionColumnUnknown - may or may not be pseudo column
     *      <LI> versionColumnNotPseudo - is NOT a pseudo column
     *      <LI> versionColumnPseudo - is a pseudo column
     *      </UL>
     *  </OL>
     *
     * @param catalog a catalog name; "" retrieves those without a
     * catalog; null 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 column description 
     * @exception SQLException if a database-access error occurs.
     */
	ResultSet getVersionColumns(String catalog, String schema,
				String table) throws SQLException;
	
    /**
     * VERSION COLUMNS PSEUDO_COLUMN - may or may not be pseudo column.
     */
	int versionColumnUnknown	= 0;

    /**
     *  VERSION COLUMNS PSEUDO_COLUMN - is NOT a pseudo column.
     */
	int versionColumnNotPseudo	= 1;

    /**
     *  VERSION COLUMNS PSEUDO_COLUMN - is a pseudo column.
     */
	int versionColumnPseudo	= 2;

    /**
     * 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
     * catalog; null 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 
     * @exception SQLException if a database-access error occurs.
     */
	ResultSet getPrimaryKeys(String catalog, String schema,
				String table) throws SQLException;

    /**
     * Get a description of the primary key columns that are
     * referenced by a table's foreign key columns (the primary keys
     * imported by a table).  They are ordered by PKTABLE_CAT,
     * PKTABLE_SCHEM, PKTABLE_NAME, and KEY_SEQ.
     *
     * <P>Each primary key column description has the following columns:
     *  <OL>
     *	<LI><B>PKTABLE_CAT</B> String => primary key table catalog 
     *      being imported (may be null)
     *	<LI><B>PKTABLE_SCHEM</B> String => primary key table schema
     *      being imported (may be null)
     *	<LI><B>PKTABLE_NAME</B> String => primary key table name
     *      being imported
     *	<LI><B>PKCOLUMN_NAME</B> String => primary key column name
     *      being imported
     *	<LI><B>FKTABLE_CAT</B> String => foreign key table catalog (may be null)
     *	<LI><B>FKTABLE_SCHEM</B> String => foreign key table schema (may be null)
     *	<LI><B>FKTABLE_NAME</B> String => foreign key table name
     *	<LI><B>FKCOLUMN_NAME</B> String => foreign key column name
     *	<LI><B>KEY_SEQ</B> short => sequence number within foreign key
     *	<LI><B>UPDATE_RULE</B> short => What happens to 
     *       foreign key when primary is updated:
     *      <UL>
     *      <LI> importedNoAction - do not allow update of primary 
     *               key if it has been imported
     *      <LI> importedKeyCascade - change imported key to agree 
     *               with primary key update
     *      <LI> importedKeySetNull - change imported key to NULL if 
     *               its primary key has been updated
     *      <LI> importedKeySetDefault - change imported key to default values 
     *               if its primary key has been updated
     *      <LI> importedKeyRestrict - same as importedKeyNoAction 
     *                                 (for ODBC 2.x compatibility)
     *      </UL>
     *	<LI><B>DELETE_RULE</B> short => What happens to 
     *      the foreign key when primary is deleted.
     *      <UL>
     *      <LI> importedKeyNoAction - do not allow delete of primary 
     *               key if it has been imported
     *      <LI> importedKeyCascade - delete rows that import a deleted key
     *      <LI> importedKeySetNull - change imported key to NULL if 
     *               its primary key has been deleted
     *      <LI> importedKeyRestrict - same as importedKeyNoAction 
     *                                 (for ODBC 2.x compatibility)
     *      <LI> importedKeySetDefault - change imported key to default if 
     *               its primary key has been deleted
     *      </UL>
     *	<LI><B>FK_NAME</B> String => foreign key name (may be null)
     *	<LI><B>PK_NAME</B> String => primary key name (may be null)
     *	<LI><B>DEFERRABILITY</B> short => can the evaluation of foreign key 
     *      constraints be deferred until commit
     *      <UL>
     *      <LI> importedKeyInitiallyDeferred - see SQL92 for definition
     *      <LI> importedKeyInitiallyImmediate - see SQL92 for definition 
     *      <LI> importedKeyNotDeferrable - see SQL92 for definition 
     *      </UL>
     *  </OL>
     *
     * @param catalog a catalog name; "" retrieves those without a
     * catalog; null 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 
     * @exception SQLException if a database-access error occurs.
     * @see #getExportedKeys 
     */
	ResultSet getImportedKeys(String catalog, String schema,
				String table) throws SQLException;

    /**
     * IMPORT KEY UPDATE_RULE and DELETE_RULE - for update, change
     * imported key to agree with primary key update; for delete,
     * delete rows that import a deleted key.
     */
	int importedKeyCascade	= 0;

    /**
     * IMPORT KEY UPDATE_RULE and DELETE_RULE - do not allow update or
     * delete of primary key if it has been imported.  
     */
	int importedKeyRestrict = 1;

    /**
     * IMPORT KEY UPDATE_RULE and DELETE_RULE - change imported key to
     * NULL if its primary key has been updated or deleted.
     */
	int importedKeySetNull  = 2;

    /**
     * IMPORT KEY UPDATE_RULE and DELETE_RULE - do not allow update or
     * delete of primary key if it has been imported.  
     */
	int importedKeyNoAction = 3;

    /**
     * IMPORT KEY UPDATE_RULE and DELETE_RULE - change imported key to
     * default values if its primary key has been updated or deleted.
     */
	int importedKeySetDefault  = 4;

    /**
     * IMPORT KEY DEFERRABILITY - see SQL92 for definition
     */
	int importedKeyInitiallyDeferred  = 5;

    /**
     * IMPORT KEY DEFERRABILITY - see SQL92 for definition
     */
	int importedKeyInitiallyImmediate  = 6;

    /**
     * IMPORT KEY DEFERRABILITY - see SQL92 for definition
     */
	int importedKeyNotDeferrable  = 7;

    /**
     * Get a description of the foreign key columns that reference a
     * table's primary key columns (the foreign keys exported by a
     * table).  They are ordered by FKTABLE_CAT, FKTABLE_SCHEM,
     * FKTABLE_NAME, and KEY_SEQ.
     *
     * <P>Each foreign key column description has the following columns:
     *  <OL>
     *	<LI><B>PKTABLE_CAT</B> String => primary key table catalog (may be null)
     *	<LI><B>PKTABLE_SCHEM</B> String => primary key table schema (may be null)
     *	<LI><B>PKTABLE_NAME</B> String => primary key table name
     *	<LI><B>PKCOLUMN_NAME</B> String => primary key column name
     *	<LI><B>FKTABLE_CAT</B> String => foreign key table catalog (may be null)
     *      being exported (may be null)
     *	<LI><B>FKTABLE_SCHEM</B> String => foreign key table schema (may be null)
     *      being exported (may be null)
     *	<LI><B>FKTABLE_NAME</B> String => foreign key table name
     *      being exported
     *	<LI><B>FKCOLUMN_NAME</B> String => foreign key column name
     *      being exported
     *	<LI><B>KEY_SEQ</B> short => sequence number within foreign key
     *	<LI><B>UPDATE_RULE</B> short => What happens to 
     *       foreign key when primary is updated:
     *      <UL>
     *      <LI> importedNoAction - do not allow update of primary 
     *               key if it has been imported
     *      <LI> importedKeyCascade - change imported key to agree 
     *               with primary key update
     *      <LI> importedKeySetNull - change imported key to NULL if 
     *               its primary key has been updated
     *      <LI> importedKeySetDefault - change imported key to default values 
     *               if its primary key has been updated
     *      <LI> importedKeyRestrict - same as importedKeyNoAction 
     *                                 (for ODBC 2.x compatibility)
     *      </UL>
     *	<LI><B>DELETE_RULE</B> short => What happens to 
     *      the foreign key when primary is deleted.
     *      <UL>
     *      <LI> importedKeyNoAction - do not allow delete of primary 
     *               key if it has been imported
     *      <LI> importedKeyCascade - delete rows that import a deleted key
     *      <LI> importedKeySetNull - change imported key to NULL if 
     *               its primary key has been deleted
     *      <LI> importedKeyRestrict - same as importedKeyNoAction 
     *                                 (for ODBC 2.x compatibility)
     *      <LI> importedKeySetDefault - change imported key to default if 
     *               its primary key has been deleted
     *      </UL>
     *	<LI><B>FK_NAME</B> String => foreign key name (may be null)
     *	<LI><B>PK_NAME</B> String => primary key name (may be null)
     *	<LI><B>DEFERRABILITY</B> short => can the evaluation of foreign key 
     *      constraints be deferred until commit
     *      <UL>
     *      <LI> importedKeyInitiallyDeferred - see SQL92 for definition
     *      <LI> importedKeyInitiallyImmediate - see SQL92 for definition 
     *      <LI> importedKeyNotDeferrable - see SQL92 for definition 
     *      </UL>
     *  </OL>
     *
     * @param catalog a catalog name; "" retrieves those without a
     * catalog; null 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 foreign key column description 
     * @exception SQLException if a database-access error occurs.
     * @see #getImportedKeys 
     */
	ResultSet getExportedKeys(String catalog, String schema,
				String table) throws SQLException;

    /**
     * Get a description of the foreign key columns in the foreign key
     * table that reference the primary key columns of the primary key
     * table (describe how one table imports another's key.) This
     * should normally return a single foreign key/primary key pair
     * (most tables only import a foreign key from a table once.)  They
     * are ordered by FKTABLE_CAT, FKTABLE_SCHEM, FKTABLE_NAME, and
     * KEY_SEQ.
     *
     * <P>Each foreign key column description has the following columns:
     *  <OL>
     *	<LI><B>PKTABLE_CAT</B> String => primary key table catalog (may be null)
     *	<LI><B>PKTABLE_SCHEM</B> String => primary key table schema (may be null)
     *	<LI><B>PKTABLE_NAME</B> String => primary key table name
     *	<LI><B>PKCOLUMN_NAME</B> String => primary key column name
     *	<LI><B>FKTABLE_CAT</B> String => foreign key table catalog (may be null)
     *      being exported (may be null)
     *	<LI><B>FKTABLE_SCHEM</B> String => foreign key table schema (may be null)
     *      being exported (may be null)
     *	<LI><B>FKTABLE_NAME</B> String => foreign key table name
     *      being exported
     *	<LI><B>FKCOLUMN_NAME</B> String => foreign key column name
     *      being exported
     *	<LI><B>KEY_SEQ</B> short => sequence number within foreign key
     *	<LI><B>UPDATE_RULE</B> short => What happens to 
     *       foreign key when primary is updated:
     *      <UL>
     *      <LI> importedNoAction - do not allow update of primary 
     *               key if it has been imported
     *      <LI> importedKeyCascade - change imported key to agree 
     *               with primary key update
     *      <LI> importedKeySetNull - change imported key to NULL if 
     *               its primary key has been updated
     *      <LI> importedKeySetDefault - change imported key to default values 
     *               if its primary key has been updated
     *      <LI> importedKeyRestrict - same as importedKeyNoAction 
     *                                 (for ODBC 2.x compatibility)
     *      </UL>
     *	<LI><B>DELETE_RULE</B> short => What happens to 
     *      the foreign key when primary is deleted.
     *      <UL>
     *      <LI> importedKeyNoAction - do not allow delete of primary 
     *               key if it has been imported
     *      <LI> importedKeyCascade - delete rows that import a deleted key
     *      <LI> importedKeySetNull - change imported key to NULL if 
     *               its primary key has been deleted
     *      <LI> importedKeyRestrict - same as importedKeyNoAction 
     *                                 (for ODBC 2.x compatibility)
     *      <LI> importedKeySetDefault - change imported key to default if 
     *               its primary key has been deleted
     *      </UL>
     *	<LI><B>FK_NAME</B> String => foreign key name (may be null)
     *	<LI><B>PK_NAME</B> String => primary key name (may be null)
     *	<LI><B>DEFERRABILITY</B> short => can the evaluation of foreign key 
     *      constraints be deferred until commit
     *      <UL>
     *      <LI> importedKeyInitiallyDeferred - see SQL92 for definition
     *      <LI> importedKeyInitiallyImmediate - see SQL92 for definition 
     *      <LI> importedKeyNotDeferrable - see SQL92 for definition 
     *      </UL>
     *  </OL>
     *
     * @param primaryCatalog a catalog name; "" retrieves those without a
     * catalog; null means drop catalog