net.sourceforge.jtds.jdbc
Class JtdsStatement

java.lang.Object
  net.sourceforge.jtds.jdbc.JtdsStatement

All Implemented Interfaces:

java.sql.Statement

Direct Known Subclasses:

JtdsPreparedStatement

public class JtdsStatement

extends java.lang.Object

implements java.sql.Statement

jTDS implementation of the java.sql.Statement interface.

NB. As allowed by the JDBC standard and like most other drivers, this implementation only allows one open result set at a time.

Implementation notes:

I experimented with allowing multiple open result sets as supported by the original jTDS but rejected this approach for the following reasons:

1. It is more difficult to ensure that there are no memory leaks and that cursors are closed if multiple open sets are allowed.
2. The use of one result set allows cursor and non cursor result sets to be derived from exeuteQuery() or execute() and getResultSet() in the same way that other drivers do.

In the event of an IO failure the setClosed() method forces this statement and associated result set to close preventing the propagation of errors. This class includes a finalize method which increases the chances of the statement being closed tidly in a pooled environment where the user has forgotten to explicitly close the statement before it goes out of scope.

Author:

Mike Hutchinson, Holger Rehn

See Also:

Statement, Connection.createStatement(), ResultSet

Field Summary

protected java.util.ArrayList	batchValues Batched SQL Statement array.
(package private) static int	BOOLEAN
(package private) static int	CLOSE_ALL_RESULTS
(package private) static int	CLOSE_CURRENT_RESULT
private int[]	closed Meaning of the one and only array element at index : 0 - this statement is open 1 - this statement is currently being closed 2 - this statement is closed
protected ColInfo[]	colMetaData The cached column meta data.
protected ConnectionJDBC2	connection The connection owning this statement object.
protected JtdsResultSet	currentResult The current ResultSet.
protected java.lang.String	cursorName The cursor name to be used for positioned updates.
(package private) static int	DATALINK
(package private) static int	DEFAULT_FETCH_SIZE
protected boolean	escapeProcessing True if SQL statements should be preprocessed.
(package private) static java.lang.Integer	EXECUTE_FAILED
protected int	fetchDirection The fetch direction for result sets.
protected int	fetchSize The fetch size (default 100, only used by cursor ResultSets).
(package private) static java.lang.String	GENKEYCOL Column name to be used for retrieving generated keys from the server: "_JTDS_GENE_RATED_KEYS_"
protected CachedResultSet	genKeyResultSet Dummy result set for getGeneratedKeys.
(package private) static int	KEEP_CURRENT_RESULT
protected int	maxFieldSize The maximum field size (not used at present).
protected int	maxRows The maximum number of rows to return (not used at present).
protected SQLDiagnostic	messages SQL Diagnostic exceptions and warnings.
(package private) static int	NO_GENERATED_KEYS
protected java.util.ArrayList	openResultSets List of open result sets.
protected int	queryTimeout The read query timeout in seconds
protected java.util.LinkedList	resultQueue List of queued results (update counts, possibly followed by a ResultSet).
protected int	resultSetConcurrency The concurrency of result sets created by this statement.
protected int	resultSetType The type of result sets created by this statement.
(package private) static int	RETURN_GENERATED_KEYS
(package private) static java.lang.Integer	SUCCESS_NO_INFO
protected TdsCore	tds The TDS object used for server access.
private int	updateCount The current update count.

Constructor Summary

(package private)

JtdsStatement(ConnectionJDBC2 connection, int resultSetType, int resultSetConcurrency) Construct a new Statement object.

Method Summary

void	addBatch(java.lang.String sql)
(package private) void	addWarning(java.sql.SQLWarning w) Add an SQLWarning object to the statement warnings list.
protected void	cacheResults() Cache as many results as possible (up to the first ResultSet).
void	cancel()
protected void	checkCursorException(java.sql.SQLException e) Check that the exception is caused by the failure to open a cursor and not by a more serious SQL error.
protected void	checkOpen() Check that this statement is still open.
void	clearBatch()
void	clearWarnings()
void	close()
(package private) void	closeAllResultSets() Close all result sets.
(package private) void	closeCurrentResultSet() Close current result set (if any).
boolean	execute(java.lang.String sql)
boolean	execute(java.lang.String sql, int autoGeneratedKeys)
boolean	execute(java.lang.String sql, int[] columnIndexes)
boolean	execute(java.lang.String sql, java.lang.String[] columnNames)
int[]	executeBatch() Execute batch of SQL Statements.
private boolean	executeImpl(java.lang.String sql, int autoGeneratedKeys, boolean update) Implements the common functionality for plain statement execute(java.lang.String) and {#link #executeUpdate}: basic checks, cleaning up of previous results, setting up and executing the query and loading the first results.
protected java.sql.SQLException	executeMSBatch(int size, int executeSize, java.util.ArrayList counts) Execute the SQL batch on a MS server.
java.sql.ResultSet	executeQuery(java.lang.String sql)
protected boolean	executeSQL(java.lang.String sql, java.lang.String spName, ParamInfo[] params, boolean update, boolean useCursor) Executes any type of SQL.
protected java.sql.ResultSet	executeSQLQuery(java.lang.String sql, java.lang.String spName, ParamInfo[] params, boolean useCursor) Executes SQL to obtain a result set.
protected java.sql.SQLException	executeSybaseBatch(int size, int executeSize, java.util.ArrayList counts) Execute the SQL batch on a Sybase server.
int	executeUpdate(java.lang.String sql)
int	executeUpdate(java.lang.String sql, int autoGeneratedKeys)
int	executeUpdate(java.lang.String sql, int[] columnIndexes)
int	executeUpdate(java.lang.String sql, java.lang.String[] columnNames)
protected void	finalize() Called when this object goes out of scope to close any ResultSet object and this statement.
java.sql.Connection	getConnection()
(package private) int	getDefaultFetchSize() Retrieve the default fetch size for this statement.
int	getFetchDirection()
int	getFetchSize()
java.sql.ResultSet	getGeneratedKeys()
int	getMaxFieldSize()
int	getMaxRows()
(package private) SQLDiagnostic	getMessages() Get the statement's warnings list.
boolean	getMoreResults()
boolean	getMoreResults(int current)
int	getQueryTimeout()
java.sql.ResultSet	getResultSet()
int	getResultSetConcurrency()
int	getResultSetHoldability()
int	getResultSetType()
(package private) TdsCore	getTds() Get the Statement's TDS object.
int	getUpdateCount()
java.sql.SQLWarning	getWarnings()
boolean	isClosed()
(package private) static void	notImplemented(java.lang.String method) Report that user tried to call a method which has not been implemented.
private boolean	processResults(boolean update) Queue up update counts into resultQueue until the end of the response is reached or a ResultSet is encountered.
protected void	reset() Resets the Statement, by cleaning up all queued and unprocessed results.
void	setCursorName(java.lang.String name)
void	setEscapeProcessing(boolean enable)
void	setFetchDirection(int direction)
void	setFetchSize(int rows)
void	setMaxFieldSize(int max)
void	setMaxRows(int max)
void	setQueryTimeout(int seconds)
protected boolean	useCursor(boolean returnKeys, java.lang.String sqlWord) Determines whether a cursor should be used based on the requested result set type and concurrency, whether a cursor name has been set, the useCursors connection property has been set, the first word in the SQL query is either SELECT or EXEC/EXECUTE and no generated keys are returned.

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

GENKEYCOL

static final java.lang.String GENKEYCOL

Column name to be used for retrieving generated keys from the server: "_JTDS_GENE_RATED_KEYS_"

See Also:

Constant Field Values

RETURN_GENERATED_KEYS

static final int RETURN_GENERATED_KEYS

See Also:

Constant Field Values

NO_GENERATED_KEYS

static final int NO_GENERATED_KEYS

See Also:

Constant Field Values

CLOSE_CURRENT_RESULT

static final int CLOSE_CURRENT_RESULT

See Also:

Constant Field Values

KEEP_CURRENT_RESULT

static final int KEEP_CURRENT_RESULT

See Also:

Constant Field Values

CLOSE_ALL_RESULTS

static final int CLOSE_ALL_RESULTS

See Also:

Constant Field Values

BOOLEAN

static final int BOOLEAN

See Also:

Constant Field Values

DATALINK

static final int DATALINK

See Also:

Constant Field Values

SUCCESS_NO_INFO

static final java.lang.Integer SUCCESS_NO_INFO

EXECUTE_FAILED

static final java.lang.Integer EXECUTE_FAILED

DEFAULT_FETCH_SIZE

static final int DEFAULT_FETCH_SIZE

See Also:

Constant Field Values

connection

protected ConnectionJDBC2 connection

The connection owning this statement object.

tds

protected TdsCore tds

The TDS object used for server access.

queryTimeout

protected int queryTimeout

The read query timeout in seconds

currentResult

protected JtdsResultSet currentResult

The current ResultSet.

updateCount

private int updateCount

The current update count.

fetchDirection

protected int fetchDirection

The fetch direction for result sets.

resultSetType

protected int resultSetType

The type of result sets created by this statement.

resultSetConcurrency

protected int resultSetConcurrency

The concurrency of result sets created by this statement.

fetchSize

protected int fetchSize

The fetch size (default 100, only used by cursor ResultSets).

cursorName

protected java.lang.String cursorName

The cursor name to be used for positioned updates.

maxFieldSize

protected int maxFieldSize

The maximum field size (not used at present).

maxRows

protected int maxRows

The maximum number of rows to return (not used at present).

escapeProcessing

protected boolean escapeProcessing

True if SQL statements should be preprocessed.

messages

protected final SQLDiagnostic messages

SQL Diagnostic exceptions and warnings.

batchValues

protected java.util.ArrayList batchValues

Batched SQL Statement array.

genKeyResultSet

protected CachedResultSet genKeyResultSet

Dummy result set for getGeneratedKeys.

resultQueue

protected final java.util.LinkedList resultQueue

List of queued results (update counts, possibly followed by a ResultSet).

openResultSets

protected java.util.ArrayList openResultSets

List of open result sets.

colMetaData

protected ColInfo[] colMetaData

The cached column meta data.

closed

private final int[] closed

Meaning of the one and only array element at index :

0	- this statement is open
1	- this statement is currently being closed
2	- this statement is closed

Constructor Detail

JtdsStatement

JtdsStatement(ConnectionJDBC2 connection,
              int resultSetType,
              int resultSetConcurrency)
        throws java.sql.SQLException

Construct a new Statement object.

Parameters:

connection - The parent connection.

resultSetType - The result set type for example TYPE_FORWARD_ONLY.

resultSetConcurrency - The concurrency for example CONCUR_READ_ONLY.

Method Detail

finalize

protected void finalize()
                 throws java.lang.Throwable

Called when this object goes out of scope to close any ResultSet object and this statement.

Throws:

java.lang.Throwable

getTds

TdsCore getTds()

Get the Statement's TDS object.

Returns:

The TDS support as a TdsCore Object.

getMessages

SQLDiagnostic getMessages()

Get the statement's warnings list.

Returns:

The warnings list as a SQLDiagnostic.

checkOpen

protected void checkOpen()
                  throws java.sql.SQLException

Check that this statement is still open.

Throws:

java.sql.SQLException - if statement closed.

checkCursorException

protected void checkCursorException(java.sql.SQLException e)
                             throws java.sql.SQLException

Check that the exception is caused by the failure to open a cursor and not by a more serious SQL error.

Parameters:

e - the exception returned by the cursor class

Throws:

java.sql.SQLException - if exception is not due to a cursor error

notImplemented

static void notImplemented(java.lang.String method)
                    throws java.sql.SQLException

Report that user tried to call a method which has not been implemented.

Parameters:

method - The method name to report in the error message.

Throws:

java.sql.SQLException

closeCurrentResultSet

void closeCurrentResultSet()
                     throws java.sql.SQLException

Close current result set (if any).

Throws:

java.sql.SQLException

closeAllResultSets

void closeAllResultSets()
                  throws java.sql.SQLException

Close all result sets.

Throws:

java.sql.SQLException

addWarning

void addWarning(java.sql.SQLWarning w)

Add an SQLWarning object to the statement warnings list.

Parameters:

w - The SQLWarning to add.

executeMSBatch

protected java.sql.SQLException executeMSBatch(int size,
                                               int executeSize,
                                               java.util.ArrayList counts)
                                        throws java.sql.SQLException

Execute the SQL batch on a MS server.

Parameters:

size - the total size of the batch

executeSize - the maximum number of statements to send in one request

counts - the returned update counts

Returns:

chained exceptions linked to a SQLException

Throws:

java.sql.SQLException - if a serious error occurs during execution

executeSybaseBatch

protected java.sql.SQLException executeSybaseBatch(int size,
                                                   int executeSize,
                                                   java.util.ArrayList counts)
                                            throws java.sql.SQLException

Execute the SQL batch on a Sybase server.

Sybase needs to have the SQL concatenated into one TDS language packet. This method will be overriden for PreparedStatements.

Parameters:

size - the total size of the batch

executeSize - the maximum number of statements to send in one request

counts - the returned update counts

Returns:

chained exceptions linked to a SQLException

Throws:

java.sql.SQLException - if a serious error occurs during execution

executeSQLQuery

protected java.sql.ResultSet executeSQLQuery(java.lang.String sql,
                                             java.lang.String spName,
                                             ParamInfo[] params,
                                             boolean useCursor)
                                      throws java.sql.SQLException

Executes SQL to obtain a result set.

Parameters:

sql - the SQL statement to execute

spName - optional stored procedure name

params - optional parameters

useCursor - whether a cursor should be created for the SQL

Returns:

the result set generated by the query

Throws:

java.sql.SQLException

executeSQL

protected boolean executeSQL(java.lang.String sql,
                             java.lang.String spName,
                             ParamInfo[] params,
                             boolean update,
                             boolean useCursor)
                      throws java.sql.SQLException

Executes any type of SQL.

Parameters:

sql - the SQL statement to execute

spName - optional stored procedure name

params - optional parameters

update - whether the caller is executeUpdate(java.lang.String)

useCursor - whether the requested result set type or concurrency or connection properties request usage of a cursor

Returns:

true if the first result is a result set

Throws:

java.sql.SQLException - if an error condition occurs

processResults

private boolean processResults(boolean update)
                        throws java.sql.SQLException

Queue up update counts into resultQueue until the end of the response is reached or a ResultSet is encountered. Calling processResults while a ResultSet is open will not close it, but will consume all remaining rows.

Parameters:

update - true if the method is called from within executeUpdate

Returns:

true if there are any results, false otherwise

Throws:

java.sql.SQLException - if an error condition occurs

cacheResults

protected void cacheResults()
                     throws java.sql.SQLException

Cache as many results as possible (up to the first ResultSet). Called by ResultSets when the end is reached.

Throws:

java.sql.SQLException

reset

protected void reset()
              throws java.sql.SQLException

Resets the Statement, by cleaning up all queued and unprocessed results. Called by all execute methods and close()

Throws:

java.sql.SQLException - if an error occurs

executeImpl

private boolean executeImpl(java.lang.String sql,
                            int autoGeneratedKeys,
                            boolean update)
                     throws java.sql.SQLException

Implements the common functionality for plain statement execute(java.lang.String) and {#link #executeUpdate}: basic checks, cleaning up of previous results, setting up and executing the query and loading the first results.

Parameters:

sql - an SQL INSERT, UPDATE or DELETE statement or an SQL statement that returns nothing, such as an SQL DDL statement

autoGeneratedKeys - a flag indicating whether auto-generated keys should be made available for retrieval

update - boolean flag indicating whether the caller is executeUpdate(java.lang.String) -- in this case an exception is thrown if the first result is not an update count and no cursor is created (direct execution)

Returns:

true if the first result is a ResultSet, false if it's an update count

Throws:

java.sql.SQLException

See Also:

execute(java.lang.String), executeUpdate(java.lang.String)

useCursor

protected boolean useCursor(boolean returnKeys,
                            java.lang.String sqlWord)

Determines whether a cursor should be used based on the requested result set type and concurrency, whether a cursor name has been set, the useCursors connection property has been set, the first word in the SQL query is either SELECT or EXEC/EXECUTE and no generated keys are returned.

Parameters:

returnKeys - indicates whether keys will be returned by the query

sqlWord - the first word in the SQL query; can be null if the caller is executeQuery(java.lang.String)

Returns:

true if a cursor should be used, false if not

getDefaultFetchSize

int getDefaultFetchSize()

Retrieve the default fetch size for this statement.

Returns:

the default fetch size for a new ResultSet

getFetchDirection

public int getFetchDirection()
                      throws java.sql.SQLException

Specified by:

getFetchDirection in interface java.sql.Statement

Throws:

java.sql.SQLException

getFetchSize

public int getFetchSize()
                 throws java.sql.SQLException

Specified by:

getFetchSize in interface java.sql.Statement

Throws:

java.sql.SQLException

getMaxFieldSize

public int getMaxFieldSize()
                    throws java.sql.SQLException

Specified by:

getMaxFieldSize in interface java.sql.Statement

Throws:

java.sql.SQLException

getMaxRows

public int getMaxRows()
               throws java.sql.SQLException

Specified by:

getMaxRows in interface java.sql.Statement

Throws:

java.sql.SQLException

getQueryTimeout

public int getQueryTimeout()
                    throws java.sql.SQLException

Specified by:

getQueryTimeout in interface java.sql.Statement

Throws:

java.sql.SQLException

getResultSetConcurrency

public int getResultSetConcurrency()
                            throws java.sql.SQLException

Specified by:

getResultSetConcurrency in interface java.sql.Statement

Throws:

java.sql.SQLException

getResultSetHoldability

public int getResultSetHoldability()
                            throws java.sql.SQLException

Specified by:

getResultSetHoldability in interface java.sql.Statement

Throws:

java.sql.SQLException

getResultSetType

public int getResultSetType()
                     throws java.sql.SQLException

Specified by:

getResultSetType in interface java.sql.Statement

Throws:

java.sql.SQLException

getUpdateCount

public int getUpdateCount()
                   throws java.sql.SQLException

Specified by:

getUpdateCount in interface java.sql.Statement

Throws:

java.sql.SQLException

cancel

public void cancel()
            throws java.sql.SQLException

Specified by:

cancel in interface java.sql.Statement

Throws:

java.sql.SQLException

clearBatch

public void clearBatch()
                throws java.sql.SQLException

Specified by:

clearBatch in interface java.sql.Statement

Throws:

java.sql.SQLException

clearWarnings

public void clearWarnings()
                   throws java.sql.SQLException

Specified by:

clearWarnings in interface java.sql.Statement

Throws:

java.sql.SQLException

close

public void close()
           throws java.sql.SQLException

Specified by:

close in interface java.sql.Statement

Throws:

java.sql.SQLException

getMoreResults

public boolean getMoreResults()
                       throws java.sql.SQLException

Specified by:

getMoreResults in interface java.sql.Statement

Throws:

java.sql.SQLException

executeBatch

public int[] executeBatch()
                   throws java.sql.SQLException,
                          java.sql.BatchUpdateException

Execute batch of SQL Statements.

The JDBC3 standard says that the behavior of this method must be consistent for any DBMS. As Sybase (and to a lesser extent SQL Server) will sometimes continue after a batch execution error, the only way to comply with the standard is to always return an array of update counts the same size as the batch list. Slots in the array beyond the last executed statement are set to EXECUTE_FAILED.

There is a problem with certain statements, returning more update counts than there are batch operations. (see bug [])

Specified by:

executeBatch in interface java.sql.Statement

Returns:

update counts as an int[]

Throws:

java.sql.SQLException

java.sql.BatchUpdateException

setFetchDirection

public void setFetchDirection(int direction)
                       throws java.sql.SQLException

Specified by:

setFetchDirection in interface java.sql.Statement

Throws:

java.sql.SQLException

setFetchSize

public void setFetchSize(int rows)
                  throws java.sql.SQLException

Specified by:

setFetchSize in interface java.sql.Statement

Throws:

java.sql.SQLException

setMaxFieldSize

public void setMaxFieldSize(int max)
                     throws java.sql.SQLException

Specified by:

setMaxFieldSize in interface java.sql.Statement

Throws:

java.sql.SQLException

setMaxRows

public void setMaxRows(int max)
                throws java.sql.SQLException

Specified by:

setMaxRows in interface java.sql.Statement

Throws:

java.sql.SQLException

setQueryTimeout

public void setQueryTimeout(int seconds)
                     throws java.sql.SQLException

Specified by:

setQueryTimeout in interface java.sql.Statement

Throws:

java.sql.SQLException

getMoreResults

public boolean getMoreResults(int current)
                       throws java.sql.SQLException

Specified by:

getMoreResults in interface java.sql.Statement

Throws:

java.sql.SQLException

setEscapeProcessing

public void setEscapeProcessing(boolean enable)
                         throws java.sql.SQLException

Specified by:

setEscapeProcessing in interface java.sql.Statement

Throws:

java.sql.SQLException

executeUpdate

public int executeUpdate(java.lang.String sql)
                  throws java.sql.SQLException

Specified by:

executeUpdate in interface java.sql.Statement

Throws:

java.sql.SQLException

addBatch

public void addBatch(java.lang.String sql)
              throws java.sql.SQLException

Specified by:

addBatch in interface java.sql.Statement

Throws:

java.sql.SQLException

setCursorName

public void setCursorName(java.lang.String name)
                   throws java.sql.SQLException

Specified by:

setCursorName in interface java.sql.Statement

Throws:

java.sql.SQLException

execute

public boolean execute(java.lang.String sql)
                throws java.sql.SQLException

Specified by:

execute in interface java.sql.Statement

Throws:

java.sql.SQLException

executeUpdate

public int executeUpdate(java.lang.String sql,
                         int autoGeneratedKeys)
                  throws java.sql.SQLException

Specified by:

executeUpdate in interface java.sql.Statement

Throws:

java.sql.SQLException

execute

public boolean execute(java.lang.String sql,
                       int autoGeneratedKeys)
                throws java.sql.SQLException

Specified by:

execute in interface java.sql.Statement

Throws:

java.sql.SQLException

executeUpdate

public int executeUpdate(java.lang.String sql,
                         int[] columnIndexes)
                  throws java.sql.SQLException

Specified by:

executeUpdate in interface java.sql.Statement

Throws:

java.sql.SQLException

execute

public boolean execute(java.lang.String sql,
                       int[] columnIndexes)
                throws java.sql.SQLException

Specified by:

execute in interface java.sql.Statement

Throws:

java.sql.SQLException

getConnection

public java.sql.Connection getConnection()
                                  throws java.sql.SQLException

Specified by:

getConnection in interface java.sql.Statement

Throws:

java.sql.SQLException

getGeneratedKeys

public java.sql.ResultSet getGeneratedKeys()
                                    throws java.sql.SQLException

Specified by:

getGeneratedKeys in interface java.sql.Statement

Throws:

java.sql.SQLException

getResultSet

public java.sql.ResultSet getResultSet()
                                throws java.sql.SQLException

Specified by:

getResultSet in interface java.sql.Statement

Throws:

java.sql.SQLException

getWarnings

public java.sql.SQLWarning getWarnings()
                                throws java.sql.SQLException

Specified by:

getWarnings in interface java.sql.Statement

Throws:

java.sql.SQLException

executeUpdate

public int executeUpdate(java.lang.String sql,
                         java.lang.String[] columnNames)
                  throws java.sql.SQLException

Specified by:

executeUpdate in interface java.sql.Statement

Throws:

java.sql.SQLException

execute

public boolean execute(java.lang.String sql,
                       java.lang.String[] columnNames)
                throws java.sql.SQLException

Specified by:

execute in interface java.sql.Statement

Throws:

java.sql.SQLException

executeQuery

public java.sql.ResultSet executeQuery(java.lang.String sql)
                                throws java.sql.SQLException

Specified by:

executeQuery in interface java.sql.Statement

Throws:

java.sql.SQLException

isClosed

public boolean isClosed()
                 throws java.sql.SQLException

Returns:

whether this JtdsStatement has been closed

Throws:

java.sql.SQLException