org.h2.command
Class Command

java.lang.Object
  org.h2.command.Command

All Implemented Interfaces:

CommandInterface

Direct Known Subclasses:

CommandContainer, CommandList

public abstract class Command
extends java.lang.Object
implements CommandInterface

Represents a SQL statement. This object is only used on the server side.

Field Summary

protected Session	session The session.
protected long	startTime The last start time.
protected Trace	trace The trace module.

Constructor Summary

Command(Parser parser, java.lang.String sql)

Method Summary

void	cancel() Cancel the statement if it is still processing.
void	checkCanceled() Check if this command has been canceled, and throw an exception if yes.
void	close() Close the statement.
ResultInterface	executeQuery(int maxrows, boolean scrollable) Execute the query.
LocalResult	executeQueryLocal(int maxrows) Execute a query and return a local result set.
int	executeUpdate() Execute the statement
ResultInterface	getMetaData() Get an empty result set containing the meta data of the result.
LocalResult	getMetaDataLocal()
abstract ObjectArray<? extends ParameterInterface>	getParameters() Get the list of parameters.
abstract boolean	isQuery() Check if this command is a query.
abstract boolean	isReadOnly() Check if this command is read only.
abstract boolean	isTransactional() Check if this command is transactional.
LocalResult	query(int maxrows) Execute a query statement, if this is possible.
abstract LocalResult	queryMeta() Get an empty result set containing the meta data.
java.lang.String	toString()
int	update() Execute an updating statement, if this is possible.

Methods inherited from class java.lang.Object

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

Field Detail

session

protected final Session session

The session.

trace

protected final Trace trace

The trace module.

startTime

protected long startTime

The last start time.

Constructor Detail

Command

public Command(Parser parser,
               java.lang.String sql)

Method Detail

isTransactional

public abstract boolean isTransactional()

Check if this command is transactional. If it is not, then it forces the current transaction to commit.

Returns:

true if it is

isQuery

public abstract boolean isQuery()

Check if this command is a query.

Specified by:

isQuery in interface CommandInterface

Returns:

true if it is

getParameters

public abstract ObjectArray<? extends ParameterInterface> getParameters()

Get the list of parameters.

Specified by:

getParameters in interface CommandInterface

Returns:

the list of parameters

isReadOnly

public abstract boolean isReadOnly()

Check if this command is read only.

Returns:

true if it is

queryMeta

public abstract LocalResult queryMeta()
                               throws java.sql.SQLException

Get an empty result set containing the meta data.

Returns:

an empty result set

Throws:

java.sql.SQLException

update

public int update()
           throws java.sql.SQLException

Execute an updating statement, if this is possible.

Returns:

the update count

Throws:

java.sql.SQLException - if the command is not an updating statement

query

public LocalResult query(int maxrows)
                  throws java.sql.SQLException

Execute a query statement, if this is possible.

Parameters:

maxrows - the maximum number of rows returned

Returns:

the local result set

Throws:

java.sql.SQLException - if the command is not a query

getMetaDataLocal

public final LocalResult getMetaDataLocal()
                                   throws java.sql.SQLException

Throws:

java.sql.SQLException

getMetaData

public final ResultInterface getMetaData()
                                  throws java.sql.SQLException

Description copied from interface: CommandInterface

Get an empty result set containing the meta data of the result.

Specified by:

getMetaData in interface CommandInterface

Returns:

the empty result

Throws:

java.sql.SQLException

executeQuery

public ResultInterface executeQuery(int maxrows,
                                    boolean scrollable)
                             throws java.sql.SQLException

Description copied from interface: CommandInterface

Execute the query.

Specified by:

executeQuery in interface CommandInterface

Parameters:

maxrows - the maximum number of rows returned

scrollable - if the result set must be scrollable

Returns:

the result

Throws:

java.sql.SQLException

executeQueryLocal

public LocalResult executeQueryLocal(int maxrows)
                              throws java.sql.SQLException

Execute a query and return a local result set. This method prepares everything and calls query(int) finally.

Parameters:

maxrows - the maximum number of rows to return

Returns:

the local result set

Throws:

java.sql.SQLException

checkCanceled

public void checkCanceled()
                   throws java.sql.SQLException

Check if this command has been canceled, and throw an exception if yes.

Throws:

java.sql.SQLException - if the statement has been canceled

executeUpdate

public int executeUpdate()
                  throws java.sql.SQLException

Description copied from interface: CommandInterface

Execute the statement

Specified by:

executeUpdate in interface CommandInterface

Returns:

the update count

Throws:

java.sql.SQLException

close

public void close()

Description copied from interface: CommandInterface

Close the statement.

Specified by:

close in interface CommandInterface

cancel

public void cancel()

Description copied from interface: CommandInterface

Cancel the statement if it is still processing.

Specified by:

cancel in interface CommandInterface

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object