package postgresql.jdbc2;
// IMPORTANT NOTE: This file implements the JDBC 2 version of the driver.
// If you make any modifications to this file, you must make sure that the
// changes are also made (if relevent) to the related JDBC 1 class in the
// postgresql.jdbc1 package.
import java.io.*;
import java.lang.*;
import java.lang.reflect.*;
import java.net.*;
import java.util.*;
import java.sql.*;
import postgresql.Field;
import postgresql.fastpath.*;
import postgresql.largeobject.*;
import postgresql.util.*;
/**
* $Id: Connection.java,v 1.2 1999/05/18 23:17:26 peter Exp $
*
* A Connection represents a session with a specific database. Within the
* context of a Connection, SQL statements are executed and results are
* returned.
*
* <P>A Connection's database is able to provide information describing
* its tables, its supported SQL grammar, its stored procedures, the
* capabilities of this connection, etc. This information is obtained
* with the getMetaData method.
*
* <p><B>Note:</B> By default, the Connection automatically commits changes
* after executing each statement. If auto-commit has been disabled, an
* explicit commit must be done or database changes will not be saved.
*
* @see java.sql.Connection
*/
public class Connection extends postgresql.Connection implements java.sql.Connection
{
// This is a cache of the DatabaseMetaData instance for this connection
protected DatabaseMetaData metadata;
/**
* SQL statements without parameters are normally executed using
* Statement objects. If the same SQL statement is executed many
* times, it is more efficient to use a PreparedStatement
*
* @return a new Statement object
* @exception SQLException passed through from the constructor
*/
public java.sql.Statement createStatement() throws SQLException
{
return new Statement(this);
}
/**
* A SQL statement with or without IN parameters can be pre-compiled
* and stored in a PreparedStatement object. This object can then
* be used to efficiently execute this statement multiple times.
*
* <B>Note:</B> This method is optimized for handling parametric
* SQL statements that benefit from precompilation if the drivers
* supports precompilation. PostgreSQL does not support precompilation.
* In this case, the statement is not sent to the database until the
* PreparedStatement is executed. This has no direct effect on users;
* however it does affect which method throws certain SQLExceptions
*
* @param sql a SQL statement that may contain one or more '?' IN
* parameter placeholders
* @return a new PreparedStatement object containing the pre-compiled
* statement.
* @exception SQLException if a database access error occurs.
*/
public java.sql.PreparedStatement prepareStatement(String sql) throws SQLException
{
return new PreparedStatement(this, sql);
}
/**
* A SQL stored procedure call statement is handled by creating a
* CallableStatement for it. The CallableStatement provides methods
* for setting up its IN and OUT parameters and methods for executing
* it.
*
* <B>Note:</B> This method is optimised for handling stored procedure
* call statements. Some drivers may send the call statement to the
* database when the prepareCall is done; others may wait until the
* CallableStatement is executed. This has no direct effect on users;
* however, it does affect which method throws certain SQLExceptions
*
* @param sql a SQL statement that may contain one or more '?' parameter
* placeholders. Typically this statement is a JDBC function call
* escape string.
* @return a new CallableStatement object containing the pre-compiled
* SQL statement
* @exception SQLException if a database access error occurs
*/
public java.sql.CallableStatement prepareCall(String sql) throws SQLException
{
throw new PSQLException("postgresql.con.call");
// return new CallableStatement(this, sql);
}
/**
* A driver may convert the JDBC sql grammar into its system's
* native SQL grammar prior to sending it; nativeSQL returns the
* native form of the statement that the driver would have sent.
*
* @param sql a SQL statement that may contain one or more '?'
* parameter placeholders
* @return the native form of this statement
* @exception SQLException if a database access error occurs
*/
public String nativeSQL(String sql) throws SQLException
{
return sql;
}
/**
* If a connection is in auto-commit mode, than all its SQL
* statements will be executed and committed as individual
* transactions. Otherwise, its SQL statements are grouped
* into transactions that are terminated by either commit()
* or rollback(). By default, new connections are in auto-
* commit mode. The commit occurs when the statement completes
* or the next execute occurs, whichever comes first. In the
* case of statements returning a ResultSet, the statement
* completes when the last row of the ResultSet has been retrieved
* or the ResultSet has been closed. In advanced cases, a single
* statement may return multiple results as well as output parameter
* values. Here the commit occurs when all results and output param
* values have been retrieved.
*
* @param autoCommit - true enables auto-commit; false disables it
* @exception SQLException if a database access error occurs
*/
public void setAutoCommit(boolean autoCommit) throws SQLException
{
if (this.autoCommit == autoCommit)
return;
if (autoCommit)
ExecSQL("end");
else
ExecSQL("begin");
this.autoCommit = autoCommit;
}
/**
* gets the current auto-commit state
*
* @return Current state of the auto-commit mode
* @exception SQLException (why?)
* @see setAutoCommit
*/
public boolean getAutoCommit() throws SQLException
{
return this.autoCommit;
}
/**
* The method commit() makes all changes made since the previous
* commit/rollback permanent and releases any database locks currently
* held by the Connection. This method should only be used when
* auto-commit has been disabled. (If autoCommit == true, then we
* just return anyhow)
*
* @exception SQLException if a database access error occurs
* @see setAutoCommit
*/
public void commit() throws SQLException
{
if (autoCommit)
return;
ExecSQL("commit");
autoCommit = true;
ExecSQL("begin");
autoCommit = false;
}
/**
* The method rollback() drops all changes made since the previous
* commit/rollback and releases any database locks currently held by
* the Connection.
*
* @exception SQLException if a database access error occurs
* @see commit
*/
public void rollback() throws SQLException
{
if (autoCommit)
return;
ExecSQL("rollback");
autoCommit = true;
ExecSQL("begin");
autoCommit = false;
}
/**
* In some cases, it is desirable to immediately release a Connection's
* database and JDBC resources instead of waiting for them to be
* automatically released (cant think why off the top of my head)
*
* <B>Note:</B> A Connection is automatically closed when it is
* garbage collected. Certain fatal errors also result in a closed
* connection.
*
* @exception SQLException if a database access error occurs
*/
public void close() throws SQLException
{
if (pg_stream != null)
{
try
{
pg_stream.close();
} catch (IOException e) {}
pg_stream = null;
}
}
/**
* Tests to see if a Connection is closed
*
* @return the status of the connection
* @exception SQLException (why?)
*/
public boolean isClosed() throws SQLException
{
return (pg_stream == null);
}
/**
* A connection's database is able to provide information describing
* its tables, its supported SQL grammar, its stored procedures, the
* capabilities of this connection, etc. This information is made
* available through a DatabaseMetaData object.
*
* @return a DatabaseMetaData object for this connection
* @exception SQLException if a database access error occurs
*/
public java.sql.DatabaseMetaData getMetaData() throws SQLException
{
if(metadata==null)
metadata = new DatabaseMetaData(this);
return metadata;
}
/**
* You can put a connection in read-only mode as a hunt to enable
* database optimizations
*
* <B>Note:</B> setReadOnly cannot be called while in the middle
* of a transaction
*
* @param readOnly - true enables read-only mode; false disables it
* @exception SQLException if a database access error occurs
*/
public void setReadOnly (boolean readOnly) throws SQLException
{
this.readOnly = readOnly;
}
/**
* Tests to see if the connection is in Read Only Mode. Note that
* we cannot really put the database in read only mode, but we pretend
* we can by returning the value of the readOnly flag
*
* @return true if the connection is read only
* @exception SQLException if a database access error occurs
*/
public boolean isReadOnly() throws SQLException
{
return readOnly;
}
/**
* A sub-space of this Connection's database may be selected by
* setting a catalog name. If the driver does not support catalogs,
* it will silently ignore this request
*
* @exception SQLException if a database access error occurs
*/
public void setCatalog(String catalog) throws SQLException
{
// No-op
}
/**
* Return the connections current catalog name, or null if no
* catalog name is set, or we dont support catalogs.
*
* @return the current catalog name or null
* @exception SQLException if a database access error occurs
*/
public String getCatalog() throws SQLException
{
return null;
}
/**
* You can call this method to try to change the transaction
* isolation level using one of the TRANSACTION_* values.
*
* <B>Note:</B> setTransactionIsolation cannot be called while
* in the middle of a transaction
*
* @param level one of the TRANSACTION_* isolation values with
* the exception of TRANSACTION_NONE; some databases may
* not support other values
* @exception SQLException if a database access error occurs
* @see java.sql.DatabaseMetaData#supportsTransactionIsolationLevel
*/
public void setTransactionIsolation(int level) throws SQLException
{
throw postgresql.Driver.notImplemented();
}
/**
* Get this Connection's current transaction isolation mode.
*
* @return the current TRANSACTION_* mode value
* @exception SQLException if a database access error occurs
*/
public int getTransactionIsolation() throws SQLException
{
return java.sql.Connection.TRANSACTION_SERIALIZABLE;
}
/**
* The first warning reported by calls on this Connection is
* returned.
*
* <B>Note:</B> Sebsequent warnings will be changed to this
* SQLWarning
*
* @return the first SQLWarning or null
* @exception SQLException if a database access error occurs
*/
public SQLWarning getWarnings() throws SQLException
{
return firstWarning;
}
/**
* After this call, getWarnings returns null until a new warning
* is reported for this connection.
*
* @exception SQLException if a database access error occurs
*/
public void clearWarnings() throws SQLException
{
firstWarning = null;
}
/**
* This overides the method in postgresql.Connection and returns a
* ResultSet.
*/
protected java.sql.ResultSet getResultSet(postgresql.Connection conn, Field[] fields, Vector tuples, String status, int updateCount) throws SQLException
{
return new postgresql.jdbc2.ResultSet((postgresql.jdbc2.Connection)conn,fields,tuples,status,updateCount);
}
// *****************
// JDBC 2 extensions
// *****************
public java.sql.Statement createStatement(int resultSetType,int resultSetConcurrency) throws SQLException
{
// normal create followed by 2 sets?
throw postgresql.Driver.notImplemented();
}
public java.sql.PreparedStatement prepareStatement(String sql,int resultSetType,int resultSetConcurrency) throws SQLException
{
// normal prepare followed by 2 sets?
throw postgresql.Driver.notImplemented();
}
public java.sql.CallableStatement prepareCall(String sql,int resultSetType,int resultSetConcurrency) throws SQLException
{
// normal prepare followed by 2 sets?
throw postgresql.Driver.notImplemented();
}
public int getResultSetConcurrency() throws SQLException
{
throw postgresql.Driver.notImplemented();
}
public int getResultSetType() throws SQLException
{
throw postgresql.Driver.notImplemented();
}
public java.util.Map getTypeMap() throws SQLException
{
throw postgresql.Driver.notImplemented();
}
public void setResultSetConcurrency(int value) throws SQLException
{
throw postgresql.Driver.notImplemented();
}
public void setResultSetType(int type) throws SQLException
{
throw postgresql.Driver.notImplemented();
}
public void setTypeMap(java.util.Map map) throws SQLException
{
throw postgresql.Driver.notImplemented();
}
}
// ***********************************************************************