databasemetadata.java

关系型数据库 Postgresql 6.5.2

  }
  
  public int getMaxCatalogNameLength() throws SQLException
  {
    // XXX-Not Implemented
    return 0;
  }
  
  /**
   * What is the maximum length of a single row?  (not including
   * blobs).  8192 is defined in PostgreSQL.
   *
   * @return max row size in bytes
   * @exception SQLException if a database access error occurs
   */
  public int getMaxRowSize() throws SQLException
  {
    return 8192;
  }
  
  /**
   * Did getMaxRowSize() include LONGVARCHAR and LONGVARBINARY
   * blobs?  We don't handle blobs yet
   *
   * @return true if so
   * @exception SQLException if a database access error occurs
   */
  public boolean doesMaxRowSizeIncludeBlobs() throws SQLException
  {
    return false;
  }
  
  /**
   * What is the maximum length of a SQL statement?
   *
   * @return max length in bytes
   * @exception SQLException if a database access error occurs
   */
  public int getMaxStatementLength() throws SQLException
  {
    return 8192;
  }
  
  /**
   * How many active statements can we have open at one time to
   * this database?  Basically, since each Statement downloads
   * the results as the query is executed, we can have many.  However,
   * we can only really have one statement per connection going
   * at once (since they are executed serially) - so we return
   * one.
   *
   * @return the maximum
   * @exception SQLException if a database access error occurs
   */
  public int getMaxStatements() throws SQLException
  {
    return 1;
  }
  
  /**
   * What is the maximum length of a table name?  This was found
   * from pg_class.relname length
   *
   * @return max name length in bytes
   * @exception SQLException if a database access error occurs
   */
  public int getMaxTableNameLength() throws SQLException
  {
    return 32;
  }
  
  /**
   * What is the maximum number of tables that can be specified
   * in a SELECT?  Theoretically, this is the same number as the
   * number of tables allowable.  In practice tho, it is much smaller
   * since the number of tables is limited by the statement, we
   * return 1024 here - this is just a number I came up with (being
   * the number of tables roughly of three characters each that you
   * can fit inside a 8192 character buffer with comma separators).
   *
   * @return the maximum
   * @exception SQLException if a database access error occurs
   */
  public int getMaxTablesInSelect() throws SQLException
  {
    return 1024;
  }
  
  /**
   * What is the maximum length of a user name?  Well, we generally
   * use UNIX like user names in PostgreSQL, so I think this would
   * be 8.  However, showing the schema for pg_user shows a length
   * for username of 32.
   *
   * @return the max name length in bytes
   * @exception SQLException if a database access error occurs
   */
  public int getMaxUserNameLength() throws SQLException
  {
    return 32;
  }
  
  
  /**
   * What is the database's default transaction isolation level?  We
   * do not support this, so all transactions are SERIALIZABLE.
   *
   * @return the default isolation level
   * @exception SQLException if a database access error occurs
   * @see Connection
   */
  public int getDefaultTransactionIsolation() throws SQLException
  {
    return Connection.TRANSACTION_SERIALIZABLE;
  }
  
  /**
   * Are transactions supported?  If not, commit and rollback are noops
   * and the isolation level is TRANSACTION_NONE.  We do support
   * transactions.	
   *
   * @return true if transactions are supported
   * @exception SQLException if a database access error occurs
   */
  public boolean supportsTransactions() throws SQLException
  {
    return true;
  }
  
  /**
   * Does the database support the given transaction isolation level?
   * We only support TRANSACTION_SERIALIZABLE
   * 
   * @param level the values are defined in java.sql.Connection
   * @return true if so
   * @exception SQLException if a database access error occurs
   * @see Connection
   */
  public boolean supportsTransactionIsolationLevel(int level) throws SQLException
  {
    if (level == Connection.TRANSACTION_SERIALIZABLE)
      return true;
    else
      return false;
  }
  
  /**
   * Are both data definition and data manipulation transactions 
   * supported?  I checked it, and could not do a CREATE TABLE
   * within a transaction, so I am assuming that we don't
   *
   * @return true if so
   * @exception SQLException if a database access error occurs
   */
  public boolean supportsDataDefinitionAndDataManipulationTransactions() throws SQLException
  {
    return false;
  }
  
  /**
   * Are only data manipulation statements withing a transaction
   * supported?
   *
   * @return true if so
   * @exception SQLException if a database access error occurs
   */
  public boolean supportsDataManipulationTransactionsOnly() throws SQLException
  {
    return true;
  }
  
  /**
   * Does a data definition statement within a transaction force
   * the transaction to commit?  I think this means something like:
   *
   * <p><pre>
   * CREATE TABLE T (A INT);
   * INSERT INTO T (A) VALUES (2);
   * BEGIN;
   * UPDATE T SET A = A + 1;
   * CREATE TABLE X (A INT);
   * SELECT A FROM T INTO X;
   * COMMIT;
   * </pre><p>
   *
   * does the CREATE TABLE call cause a commit?  The answer is no.  
   *
   * @return true if so
   * @exception SQLException if a database access error occurs
   */
  public boolean dataDefinitionCausesTransactionCommit() throws SQLException
  {
    return false;
  }
  
  /**
   * Is a data definition statement within a transaction ignored?
   * It seems to be (from experiment in previous method)
   *
   * @return true if so
   * @exception SQLException if a database access error occurs
   */
  public boolean dataDefinitionIgnoredInTransactions() throws SQLException
  {
    return true;
  }
  
  /**
   * 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 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><b>Field 4</b> reserved (make it null)
   * <li><b>Field 5</b> reserved (make it null)
   * <li><b>Field 6</b> reserved (make it null)
   * <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 criteria
   * @param schemaParrern - a schema name pattern; "" retrieves those
   *	without a schema - we ignore this parameter
   * @param procedureNamePattern - a procedure name pattern
   * @return ResultSet - each row is a procedure description
   * @exception SQLException if a database access error occurs
   */
  public java.sql.ResultSet getProcedures(String catalog, String schemaPattern, String procedureNamePattern) throws SQLException
  {
    // the field descriptors for the new ResultSet
    Field f[] = new Field[8];
    java.sql.ResultSet r;	// ResultSet for the SQL query that we need to do
    Vector v = new Vector();		// The new ResultSet tuple stuff
    
    byte remarks[] = defaultRemarks;
    
    f[0] = new Field(connection, "PROCEDURE_CAT",   iVarcharOid, 32);
    f[1] = new Field(connection, "PROCEDURE_SCHEM", iVarcharOid, 32);
    f[2] = new Field(connection, "PROCEDURE_NAME",  iVarcharOid, 32);
    f[3] = f[4] = f[5] = null;	// reserved, must be null for now
    f[6] = new Field(connection, "REMARKS",	   iVarcharOid, 8192);
    f[7] = new Field(connection, "PROCEDURE_TYPE", iInt2Oid,	2);
    
    // If the pattern is null, then set it to the default
    if(procedureNamePattern==null)
      procedureNamePattern="%";
    
    r = connection.ExecSQL("select proname, proretset from pg_proc where proname like '"+procedureNamePattern.toLowerCase()+"' order by proname");
    
    while (r.next())
      {
	byte[][] tuple = new byte[8][0];
	
	tuple[0] = null;			// Catalog name
	tuple[1] = null;			// Schema name
	tuple[2] = r.getBytes(1);		// Procedure name
	tuple[3] = tuple[4] = tuple[5] = null;	// Reserved
	tuple[6] = remarks;			// Remarks
	
	if (r.getBoolean(2))
	  tuple[7] = Integer.toString(java.sql.DatabaseMetaData.procedureReturnsResult).getBytes();
	else
	  tuple[7] = Integer.toString(java.sql.DatabaseMetaData.procedureNoResult).getBytes();
	
	v.addElement(tuple);
      }
    return new ResultSet(connection, f, v, "OK", 1);
  }
  
  /**
   * Get a description of a catalog's stored procedure parameters
   * and result columns.
   *
   * <p>Only descriptions matching the schema, procedure and parameter
   * name criteria are returned. They are ordered by PROCEDURE_SCHEM
   * and PROCEDURE_NAME. Within this, the return value, if any, is
   * first. Next are the parameter descriptions in call order. The
   * column descriptions follow in column number order.
   *
   * <p>Each row in the ResultSet is a parameter description or column 
   * description with the following fields:
   * <ol>
   * <li><b>PROCEDURE_CAT</b> String => procedure catalog (may be null)
   * <li><b>PROCEDURE_SCHE</b>M String => procedure schema (may be null)
   * <li><b>PROCEDURE_NAME</b> String => procedure name
   * <li><b>COLUMN_NAME</b> String => column/parameter name
   * <li><b>COLUMN_TYPE</b> Short => kind of column/parameter:
   * <ul><li>procedureColumnUnknown - nobody knows
   * <li>procedureColumnIn - IN parameter
   * <li>procedureColumnInOut - INOUT parameter
   * <li>procedureColumnOut - OUT parameter
   * <li>procedureColumnReturn - procedure return value
   * <li>procedureColumnResult - result column in ResultSet
   * </ul>
   * <li><b>DATA_TYPE</b> short => SQL type from java.sql.Types
   * <li><b>TYPE_NAME</b> String => SQL type name
   * <li><b>PRECISION</b> int => precision
   * <li><b>LENGTH</b> int => length in bytes of data
   * <li><b>SCALE</b> short => scale
   * <li><b>RADIX</b> short => radix
   * <li><b>NULLABLE</b> short => can it contain NULL?
   * <ul><li>procedureNoNulls - does not allow NULL values
   * <li>procedureNullable - allows NULL values
   * <li>procedureNullableUnknown - nullability unknown
   * <li><b>REMARKS</b> String => comment describing parameter/column
   * </ol>
   * @param catalog This is ignored in postgresql, advise this is set to null
   * @param schemaPattern This is ignored in postgresql, advise this is set to null
   * @param procedureNamePattern a procedure name pattern
   * @param columnNamePattern a column name pattern
   * @return each row is a stored procedure parameter or column description
   * @exception SQLException if a database-access error occurs
   * @see #getSearchStringEscape
   */
  // Implementation note: This is required for Borland's JBuilder to work
  public java.sql.ResultSet getProcedureColumns(String catalog, String schemaPattern, String procedureNamePattern, String columnNamePattern) throws SQLException
  {
    if(procedureNamePattern==null)
      procedureNamePattern="%";
    
    if(columnNamePattern==null)
      columnNamePattern="%";
    
    // for now, this returns an empty result set.
    Field f[] = new Field[13];
    ResultSet r;	// ResultSet for the SQL query that we need to do
    Vector v = new Vector();		// The new ResultSet tuple stuff
    
    f[0] = new Field(connection, new String("PROCEDURE_CAT"), iVarcharOid, 32);
    f[1] = new Field(connection, new String("PROCEDURE_SCHEM"), iVarcharOid, 32);
    f[2] = new Field(connection, new String("PROCEDURE_NAME"), iVarcharOid, 32);
    f[3] = new Field(connection, new String("COLUMN_NAME"), iVarcharOid, 32);
    f[4] = new Field(connection, new String("COLUMN_TYPE"), iInt2Oid, 2);
    f[5] = new Field(connection, new String("DATA_TYPE"), iInt2Oid, 2);
    f[6] = new Field(connection, new String("TYPE_NAME"), iVarcharOid, 32);
    f[7] = new Field(connection, new String("PRECISION"), iInt4Oid, 4);
    f[8] = new Field(connection, new String("LENGTH"), iInt4Oid, 4);
    f[9] = new Field(connection, new String("SCALE"), iInt2Oid, 2);
    f[10] = new Field(connection, new String("RADIX"), iInt2Oid, 2);
    f[11] = new Field(connection, new String("NULLABLE"), iInt2Oid, 2);
    f[12] = new Field(connection, new String("REMARKS"), iVarcharOid, 32);
    
    // add query loop here
    
    return new ResultSet(connection, f, v, "OK", 1);
  }
  
  /**
   * Get a description of tables available in a catalog.              
   *
   * <p>Only table descriptions matching the catalog, schema, table
   * name and type criteria are returned. They are ordered by
   * TABLE_TYPE, TABLE_SCHEM and TABLE_NAME.                      
   * 
   * <p>Each table 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>TABLE_TYPE</b> String => table type. Typical types are "TABLE",
   * "VIEW", "SYSTEM TABLE", "GLOBAL TEMPORARY", "LOCAL
   * TEMPORARY", "ALIAS", "SYNONYM".                             
   * <li><b>REMARKS</b> String => explanatory comment on the table
   * </ol>
   *
   * <p>The valid values for the types parameter are:
   * "TABLE", "INDEX", "LARGE OBJECT", "SEQUENCE", "SYSTEM TABLE" and
   * "SYSTEM INDEX"
   *
   * @param catalog a catalog name; For postgresql, this is ignored, and
   * should be set to null
   * @param schemaPattern a schema name pattern; For postgresql, this is ignored, and
   * should be set to null
   * @param tableNamePattern a table name pattern. For all tables this should be "%"
   * @param types a list of table types to include; null returns
   * all types
   * @return each row is a table description      
   * @exception SQLException if a database-access error occurs.
   */
  public java.sql.ResultSet getTables(String catalog, String schemaPattern, String tableNamePattern, String types[]) throws SQLException
  {
    // Handle default value for types
    if(types==null)
      types = defaultTableTypes;
    
    if(tableNamePattern==null)
      tableNamePattern="%";
    
    // the field descriptors for the new ResultSet
    Field f[] = new Field[5];
    java.sql.ResultSet r;	// ResultSet for the SQL query that we need to do
    Vector v = new Vector();		// The new ResultSet tuple stuff
    
    f[0] = new Field(connection, new String("TABLE_CAT"), iVarcharOid, 32);
    f[1] = new Field(connection, new String("TABLE_SCHEM"), iVarcharOid, 32);
    f[2] = new Field(connection, new String("TABLE_NAME"), iVarcharOid, 32);
    f[3] = new Field(connection, new String("TABLE_TYPE"), iVarcharOid, 32);
    f[4] = new Field(connection, new String("REMARKS"), iVarcharOid, 32);
    
    // Now form the query