databasemetadata.java

一个JDBC数据库连接的组件

     */
	boolean supportsSubqueriesInComparisons() throws SQLException;

    /**
     * Are subqueries in 'exists' expressions supported?
     *
     * A JDBC-Compliant driver always returns true.
     *
     * @return true if so
     * @exception SQLException if a database-access error occurs.
     */
	boolean supportsSubqueriesInExists() throws SQLException;

    /**
     * Are subqueries in 'in' statements supported?
     *
     * A JDBC-Compliant driver always returns true.
     *
     * @return true if so
     * @exception SQLException if a database-access error occurs.
     */
	boolean supportsSubqueriesInIns() throws SQLException;

    /**
     * Are subqueries in quantified expressions supported?
     *
     * A JDBC-Compliant driver always returns true.
     *
     * @return true if so
     * @exception SQLException if a database-access error occurs.
     */
	boolean supportsSubqueriesInQuantifieds() throws SQLException;

    /**
     * Are correlated subqueries supported?
     *
     * A JDBC-Compliant driver always returns true.
     *
     * @return true if so
     * @exception SQLException if a database-access error occurs.
     */
	boolean supportsCorrelatedSubqueries() throws SQLException;

    /**
     * Is SQL UNION supported?
     *
     * @return true if so
     * @exception SQLException if a database-access error occurs.
     */
	boolean supportsUnion() throws SQLException;

    /**
     * Is SQL UNION ALL supported?
     *
     * @return true if so
     * @exception SQLException if a database-access error occurs.
     */
	boolean supportsUnionAll() throws SQLException;

    /**
     * Can cursors remain open across commits? 
     * 
     * @return true if cursors always remain open; false if they might not remain open
     * @exception SQLException if a database-access error occurs.
     */
	boolean supportsOpenCursorsAcrossCommit() throws SQLException;

    /**
     * Can cursors remain open across rollbacks?
     * 
     * @return true if cursors always remain open; false if they might not remain open
     * @exception SQLException if a database-access error occurs.
     */
	boolean supportsOpenCursorsAcrossRollback() throws SQLException;

    /**
     * Can statements remain open across commits?
     * 
     * @return true if statements always remain open; false if they might not remain open
     * @exception SQLException if a database-access error occurs.
     */
	boolean supportsOpenStatementsAcrossCommit() throws SQLException;

    /**
     * Can statements remain open across rollbacks?
     * 
     * @return true if statements always remain open; false if they might not remain open
     * @exception SQLException if a database-access error occurs.
     */
	boolean supportsOpenStatementsAcrossRollback() throws SQLException;

	

    //----------------------------------------------------------------------
    // 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
     * @exception SQLException if a database-access error occurs.
     */
	int getMaxBinaryLiteralLength() throws SQLException;

    /**
     * What's the max length for a character literal?
     *
     * @return max literal length
     * @exception SQLException if a database-access error occurs.
     */
	int getMaxCharLiteralLength() throws SQLException;

    /**
     * What's the limit on column name length?
     *
     * @return max literal length
     * @exception SQLException if a database-access error occurs.
     */
	int getMaxColumnNameLength() throws SQLException;

    /**
     * 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.
     */
	int getMaxColumnsInGroupBy() throws SQLException;

    /**
     * What's the maximum number of columns allowed in an index?
     *
     * @return max columns
     * @exception SQLException if a database-access error occurs.
     */
	int getMaxColumnsInIndex() throws SQLException;

    /**
     * What's the maximum number of columns in an "ORDER BY" clause?
     *
     * @return max columns
     * @exception SQLException if a database-access error occurs.
     */
	int getMaxColumnsInOrderBy() throws SQLException;

    /**
     * What's the maximum number of columns in a "SELECT" list?
     *
     * @return max columns
     * @exception SQLException if a database-access error occurs.
     */
	int getMaxColumnsInSelect() throws SQLException;

    /**
     * What's the maximum number of columns in a table?
     *
     * @return max columns
     * @exception SQLException if a database-access error occurs.
     */
	int getMaxColumnsInTable() throws SQLException;

    /**
     * How many active connections can we have at a time to this database?
     *
     * @return max connections
     * @exception SQLException if a database-access error occurs.
     */
	int getMaxConnections() throws SQLException;

    /**
     * What's the maximum cursor name length?
     *
     * @return max cursor name length in bytes
     * @exception SQLException if a database-access error occurs.
     */
	int getMaxCursorNameLength() throws SQLException;

    /**
     * What's the maximum length of an index (in bytes)?	
     *
     * @return max index length in bytes
     * @exception SQLException if a database-access error occurs.
     */
	int getMaxIndexLength() throws SQLException;

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

    /**
     * What's the maximum length of a procedure name?
     *
     * @return max name length in bytes 
     * @exception SQLException if a database-access error occurs.
     */
	int getMaxProcedureNameLength() throws SQLException;

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

    /**
     * What's the maximum length of a single row?
     *
     * @return max row size in bytes
     * @exception SQLException if a database-access error occurs.
     */
	int getMaxRowSize() throws SQLException;

    /**
     * Did getMaxRowSize() include LONGVARCHAR and LONGVARBINARY
     * blobs?
     *
     * @return true if so 
     * @exception SQLException if a database-access error occurs.
     */
	boolean doesMaxRowSizeIncludeBlobs() throws SQLException;

    /**
     * What's the maximum length of a SQL statement?
     *
     * @return max length in bytes
     * @exception SQLException if a database-access error occurs.
     */
	int getMaxStatementLength() throws SQLException;

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

    /**
     * What's the maximum length of a table name?
     *
     * @return max name length in bytes
     * @exception SQLException if a database-access error occurs.
     */
	int getMaxTableNameLength() throws SQLException;

    /**
     * What's the maximum number of tables in a SELECT?
     *
     * @return the maximum
     * @exception SQLException if a database-access error occurs.
     */
	int getMaxTablesInSelect() throws SQLException;

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

    //----------------------------------------------------------------------

    /**
     * What's the database's default transaction isolation level?  The
     * values are defined in java.sql.Connection.
     *
     * @return the default isolation level 
     * @exception SQLException if a database-access error occurs.
     * @see Connection
     */
	int getDefaultTransactionIsolation() throws SQLException;

    /**
     * Are transactions supported? If not, commit is a noop and the
     * isolation level is TRANSACTION_NONE.
     *
     * @return true if transactions are supported 
     * @exception SQLException if a database-access error occurs.
     */
	boolean supportsTransactions() throws SQLException;

    /**
     * Does the database support the given transaction isolation level?
     *
     * @param level the values are defined in java.sql.Connection
     * @return true if so 
     * @exception SQLException if a database-access error occurs.
     * @see Connection
     */
	boolean supportsTransactionIsolationLevel(int level)
							throws SQLException;

    /**
     * Are both data definition and data manipulation statements
     * within a transaction supported?
     *
     * @return true if so 
     * @exception SQLException if a database-access error occurs.
     */
	boolean supportsDataDefinitionAndDataManipulationTransactions()
							 throws SQLException;
    /**
     * Are only data manipulation statements within a transaction
     * supported?
     *
     * @return true if so
     * @exception SQLException if a database-access error occurs.
     */
	boolean supportsDataManipulationTransactionsOnly()
							throws SQLException;
    /**
     * Does a data definition statement within a transaction force the
     * transaction to commit?
     *
     * @return true if so 
     * @exception SQLException if a database-access error occurs.
     */
	boolean dataDefinitionCausesTransactionCommit()
							throws SQLException;
    /**
     * Is a data definition statement within a transaction ignored?
     *
     * @return true if so 
     * @exception SQLException if a database-access error occurs.
     */
	boolean dataDefinitionIgnoredInTransactions()
							throws SQLException;


    /**
     * Get a description of stored procedures available in a
     * catalog.
     *
     * <P>Only procedure descriptions matching the schema and
     * procedure name criteria are returned.  They are ordered by
     * PROCEDURE_SCHEM, and PROCEDURE_NAME.
     *
     * <P>Each procedure description has the the following columns:
     *  <OL>
     *	<LI><B>PROCEDURE_CAT</B> String => procedure catalog (may be null)
     *	<LI><B>PROCEDURE_SCHEM</B> String => procedure schema (may be null)
     *	<LI><B>PROCEDURE_NAME</B> String => procedure name
     *  <LI> reserved for future use
     *  <LI> reserved for future use
     *  <LI> reserved for future use
     *	<LI><B>REMARKS</B> String => explanatory comment on the procedure
     *	<LI><B>PROCEDURE_TYPE</B> short => kind of procedure:
     *      <UL>
     *      <LI> procedureResultUnknown - May return a result
     *      <LI> procedureNoResult - Does not return a result
     *      <LI> procedureReturnsResult - Returns a result
     *      </UL>
     *  </OL>
     *
     * @param catalog a catalog name; "" retrieves those without a
     * catalog; null means drop catalog name from the selection criteria
     * @param schemaPattern a schema name pattern; "" retrieves those
     * without a schema
     * @param procedureNamePattern a procedure name pattern 
     * @return ResultSet - each row is a procedure description 
     * @exception SQLException if a database-access error occurs.