The object used for executing a static SQL statement
and obtaining the results produced by it.
Only one
ResultSet object per
Statement object
can be open at any point in
time. Therefore, if the reading of one
ResultSet object is interleaved
with the reading of another, each must have been generated by
different
Statement objects. All statement
execute
methods implicitly close a statment's current
ResultSet object
if an open one exists.
addBatch
public void addBatch(String sql)
throws SQLException Adds an SQL command to the current batch of commmands for this
Statement object. This method is optional.
sql - typically this is a static SQL INSERT or
UPDATE statement
addWarning
protected void addWarning(SQLWarning warning)
cancel
public void cancel()
throws SQLException Cancels this Statement object if both the DBMS and
driver support aborting an SQL statement.
This method can be used by one thread to cancel a statement that
is being executed by another thread.
clearBatch
public void clearBatch()
throws SQLException Makes the set of commands in the current batch empty.
This method is optional.
clearWarnings
public void clearWarnings()
throws SQLException Clears all the warnings reported on this Statement
object. After a call to this method,
the method getWarnings will return
null until a new warning is reported for this
Statement object.
close
public void close()
throws SQLException Releases this
Statement object's database
and JDBC resources immediately instead of waiting for
this to happen when it is automatically closed.
It is generally good practice to release resources as soon as
you are finished with them to avoid tying up database
resources.
Note: A
Statement object is automatically closed when it is
garbage collected. When a
Statement object is closed, its current
ResultSet object, if one exists, is also closed.
completeStatement
public void completeStatement()
throws SQLException
execute
public boolean execute(String sql)
throws SQLException Executes an SQL statement that may return multiple results.
Under some (uncommon) situations a single SQL statement may return
multiple result sets and/or update counts. Normally you can ignore
this unless you are (1) executing a stored procedure that you know may
return multiple results or (2) you are dynamically executing an
unknown SQL string. The methods execute,
getMoreResults, getResultSet,
and getUpdateCount let you navigate through multiple results.
The execute method executes an SQL statement and indicates the
form of the first result. You can then use the methods
getResultSet or getUpdateCount
to retrieve the result, and getMoreResults to
move to any subsequent result(s).
true if the next result is a ResultSet object;
false if it is an update count or there are no more results
executeBatch
public int[] executeBatch()
throws SQLException Submits a batch of commands to the database for execution and
if all commands execute successfully, returns an array of update counts.
The
int elements of the array that is returned are ordered
to correspond to the commands in the batch, which are ordered
according to the order in which they were added to the batch.
The elements in the array returned by the method
executeBatch
may be one of the following:
- A number greater than or equal to zero -- indicates that the
command was processed successfully and is an update count giving the
number of rows in the database that were affected by the command's
execution
- A value of
-2 -- indicates that the command was
processed successfully but that the number of rows affected is
unknown
If one of the commands in a batch update fails to execute properly,
this method throws a BatchUpdateException, and a JDBC
driver may or may not continue to process the remaining commands in
the batch. However, the driver's behavior must be consistent with a
particular DBMS, either always continuing to process commands or never
continuing to process commands. If the driver continues processing
after a failure, the array returned by the method
BatchUpdateException.getUpdateCounts
will contain as many elements as there are commands in the batch, and
at least one of the elements will be the following:
- A value of
-3 -- indicates that the command failed
to execute successfully and occurs only if a driver continues to
process commands after a command fails
A driver is not required to implement this method.
The possible implementations and return values have been modified in
the Java 2 SDK, Standard Edition, version 1.3 to
accommodate the option of continuing to proccess commands in a batch
update after a
BatchUpdateException obejct has been thrown.
- an array of update counts containing one element for each
command in the batch. The elements of the array are ordered according
to the order in which commands were added to the batch.
executeQuery
public ResultSet executeQuery(String sql)
throws SQLException Executes an SQL statement that returns a single ResultSet object.
sql - typically this is a static SQL SELECT statement
- a
ResultSet object that contains the data produced by the
given query; never null
executeUpdate
public int executeUpdate(String sql)
throws SQLException Executes an SQL INSERT, UPDATE or
DELETE statement. In addition,
SQL statements that return nothing, such as SQL DDL statements,
can be executed.
sql - an SQL INSERT, UPDATE or
DELETE statement or an SQL statement that returns nothing
- either the row count for
INSERT, UPDATE
or DELETE statements, or 0 for SQL statements that return nothing
finalize
protected void finalize()
throws Throwable
forgetResultSet
public void forgetResultSet()
getConnection
public Connection getConnection()
throws SQLException Returns the Connection object that produced this
Statement object.
- the connection that produced this statement
getFetchDirection
public int getFetchDirection()
throws SQLException Retrieves the direction for fetching rows from
database tables that is the default for result sets
generated from this Statement object.
If this Statement object has not set
a fetch direction by calling the method setFetchDirection,
the return value is implementation-specific.
- the default fetch direction for result sets generated
from this
Statement object
getFetchSize
public int getFetchSize()
throws SQLException Retrieves the number of result set rows that is the default
fetch size for result sets
generated from this Statement object.
If this Statement object has not set
a fetch size by calling the method setFetchSize,
the return value is implementation-specific.
- the default fetch size for result sets generated
from this
Statement object
getMaxFieldSize
public int getMaxFieldSize()
throws SQLException Returns the maximum number of bytes allowed
for any column value.
This limit is the maximum number of bytes that can be
returned for any column value.
The limit applies only to BINARY,
VARBINARY, LONGVARBINARY, CHAR, VARCHAR, and LONGVARCHAR
columns. If the limit is exceeded, the excess data is silently
discarded.
- the current max column size limit; zero means unlimited
getMaxRows
public int getMaxRows()
throws SQLException Retrieves the maximum number of rows that a
ResultSet object can contain. If the limit is exceeded, the excess
rows are silently dropped.
- the current max row limit; zero means unlimited
getMoreResults
public boolean getMoreResults()
throws SQLException Moves to a
Statement object's next result. It returns
true if this result is a
ResultSet object.
This method also implicitly closes any current
ResultSet
object obtained with the method
getResultSet.
There are no more results when the following is true:
(!getMoreResults() && (getUpdateCount() == -1)
true if the next result is a ResultSet object;
false if it is an update count or there are no more results
getMoreResults
public boolean getMoreResults(int mode)
throws SQLException
getQueryTimeout
public int getQueryTimeout()
throws SQLException Retrieves the number of seconds the driver will
wait for a Statement object to execute. If the limit is exceeded, a
SQLException is thrown.
- the current query timeout limit in seconds; zero means unlimited
getResultSet
public ResultSet getResultSet()
throws SQLException Returns the current result as a ResultSet object.
This method should be called only once per result.
Calling this method twice with autocommit on and used will probably
throw an inappropriate or uninformative exception.
- the current result as a
ResultSet object;
null if the result is an update count or there are no more results
getResultSet
public ResultSet getResultSet(boolean trimStrings)
throws SQLException
getResultSetConcurrency
public int getResultSetConcurrency()
throws SQLException Retrieves the result set concurrency for ResultSet objects
generated by this Statement object.
- either
ResultSet.CONCUR_READ_ONLY or
ResultSet.CONCUR_UPDATABLE
getResultSetHoldability
public int getResultSetHoldability()
throws SQLException Retrieves the result set holdability for ResultSet objects
generated by this Statement object.
getResultSetType
public int getResultSetType()
throws SQLException Retrieves the result set type for ResultSet objects
generated by this Statement object.
- one of
ResultSet.TYPE_FORWARD_ONLY,
ResultSet.TYPE_SCROLL_INSENSITIVE, or
ResultSet.TYPE_SCROLL_SENSITIVE
getSynchronizationObject
public Object getSynchronizationObject()
throws SQLException Get synchronization object for this statement object.
- getSynchronizationObject in interface Synchronizable
- object that will be used for synchronization.
getUpdateCount
public int getUpdateCount()
throws SQLException Returns the current result as an update count;
if the result is a ResultSet object or there are no more results, -1
is returned. This method should be called only once per result.
- the current result as an update count; -1 if the current result is a
ResultSet object or there are no more results
getWarnings
public SQLWarning getWarnings()
throws SQLException Retrieves the first warning reported by calls on this
Statement object.
Subsequent
Statement object warnings will be chained to this
SQLWarning object.
The warning chain is automatically cleared each time
a statement is (re)executed.
Note: If you are processing a
ResultSet object, any
warnings associated with reads on that
ResultSet object
will be chained on it.
- the first
SQLWarning object or null
internalExecute
protected boolean internalExecute(String sql)
throws GDSException,
SQLException
isExecuteProcedureStatement
protected boolean isExecuteProcedureStatement(String sql)
throws SQLException This method checks if supplied statement is executing procedure or
it is generic statement. This check is needed to handle correctly
parameters that are returned from non-selectable procedures.
sql - SQL statement to check
true if supplied statement is EXECUTE PROCEDURE
type of statement.
nativeSQL
protected String nativeSQL(String sql)
throws SQLException
notifyStatementCompleted
protected void notifyStatementCompleted()
throws SQLException
notifyStatementCompleted
protected void notifyStatementCompleted(boolean success)
throws SQLException
notifyStatementStarted
protected void notifyStatementStarted()
throws SQLException
notifyStatementStarted
protected void notifyStatementStarted(boolean closeResultSet)
throws SQLException
prepareFixedStatement
protected void prepareFixedStatement(String sql,
boolean describeBind)
throws GDSException,
SQLException
setCursorName
public void setCursorName(String name)
throws SQLException Defines the SQL cursor name that will be used by
subsequent
Statement object
execute methods.
This name can then be
used in SQL positioned update/delete statements to identify the
current row in the
ResultSet object generated by this statement. If
the database doesn't support positioned update/delete, this
method is a noop. To insure that a cursor has the proper isolation
level to support updates, the cursor's
SELECT statement should be
of the form 'select for update ...'. If the 'for update' phrase is
omitted, positioned updates may fail.
Note: By definition, positioned update/delete
execution must be done by a different
Statement object than the one
which generated the
ResultSet object being used for positioning. Also,
cursor names must be unique within a connection.
name - the new cursor name, which must be unique within
a connection
setEscapeProcessing
public void setEscapeProcessing(boolean enable)
throws SQLException Sets escape processing on or off.
If escape scanning is on (the default), the driver will do
escape substitution before sending the SQL to the database.
Note: Since prepared statements have usually been parsed prior
to making this call, disabling escape processing for prepared
statements will have no effect.
enable - true to enable; false to disable
setFetchDirection
public void setFetchDirection(int direction)
throws SQLException Gives the driver a hint as to the direction in which
the rows in a result set
will be processed. The hint applies only to result sets created
using this
Statement object. The default value is
ResultSet.FETCH_FORWARD.
Note that this method sets the default fetch direction for
result sets generated by this
Statement object.
Each result set has its own methods for getting and setting
its own fetch direction.
direction - the initial direction for processing rows
setFetchSize
public void setFetchSize(int rows)
throws SQLException Gives the JDBC driver a hint as to the number of rows that should
be fetched from the database when more rows are needed. The number
of rows specified affects only result sets created using this
statement. If the value specified is zero, then the hint is ignored.
The default value is zero.
rows - the number of rows to fetch
setMaxFieldSize
public void setMaxFieldSize(int max)
throws SQLException Sets the limit for the maximum number of bytes in a column to
the given number of bytes. This is the maximum number of bytes
that can be returned for any column value. This limit applies
only to BINARY, VARBINARY,
LONGVARBINARY, CHAR, VARCHAR, and
LONGVARCHAR fields. If the limit is exceeded, the excess data
is silently discarded. For maximum portability, use values
greater than 256.
max - the new max column size limit; zero means unlimited
setMaxRows
public void setMaxRows(int max)
throws SQLException Sets the limit for the maximum number of rows that any
ResultSet object can contain to the given number.
If the limit is exceeded, the excess
rows are silently dropped.
max - the new max rows limit; zero means unlimited
setQueryTimeout
public void setQueryTimeout(int seconds)
throws SQLException Sets the number of seconds the driver will
wait for a Statement object to execute to the given number of seconds.
If the limit is exceeded, an SQLException is thrown.
seconds - the new query timeout limit in seconds; zero means
unlimited
toArray
protected int[] toArray(Collection list)
Convert collection of Integer elements into array of int.
list - collection of integer elements.