Interface java.sql.Statement

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Interface java.sql.Statement

All Known Subinterfaces:: CallableStatement, PreparedStatement

public abstract interface Statement

A Statement object is used for executing a static SQL statement and obtaining the results produced by it.

Only one ResultSet per Statement can be open at any point in time. Therefore, if the reading of one ResultSet is interleaved with the reading of another, each must have been generated by different Statements. All statement execute methods implicitly close a statment's current ResultSet if an open one exists.

See Also:: Connection.createStatement(), ResultSet

Method Summary
void	addBatch(String sql) JDBC 2.0 Adds a SQL command to the current batch of commmands for the statement.
void	cancel() Cancel can be used by one thread to cancel a statement that is being executed by another thread.
void	clearBatch() JDBC 2.0 Make the set of commands in the current batch empty.
void	clearWarnings() After this call, getWarnings returns null until a new warning is reported for this Statement.
void	close() In many cases, it is desirable to immediately release a Statements's database and JDBC resources instead of waiting for this to happen when it is automatically closed; the close method provides this immediate release.
boolean	execute(String sql) Execute a SQL statement that may return multiple results.
int[]	executeBatch() JDBC 2.0 Submit a batch of commands to the database for execution.
ResultSet	executeQuery(String sql) Execute a SQL statement that returns a single ResultSet.
int	executeUpdate(String sql) Execute a SQL INSERT, UPDATE or DELETE statement.
Connection	getConnection() JDBC 2.0 Return the Connection that produced the Statement.
int	getFetchDirection() JDBC 2.0 Determine the fetch direction.
int	getFetchSize() JDBC 2.0 Determine the default fetch size.
int	getMaxFieldSize() The maxFieldSize limit (in bytes) is the maximum amount of data returned for any column value; it only applies to BINARY, VARBINARY, LONGVARBINARY, CHAR, VARCHAR, and LONGVARCHAR columns.
int	getMaxRows() The maxRows limit is the maximum number of rows that a ResultSet can contain.
boolean	getMoreResults() getMoreResults moves to a Statement's next result.
int	getQueryTimeout() The queryTimeout limit is the number of seconds the driver will wait for a Statement to execute.
ResultSet	getResultSet() getResultSet returns the current result as a ResultSet.
int	getResultSetConcurrency() JDBC 2.0 Determine the result set concurrency.
int	getResultSetType() JDBC 2.0 Determine the result set type.
int	getUpdateCount() getUpdateCount returns the current result as an update count; if the result is a ResultSet or there are no more results, -1 is returned.
SQLWarning	getWarnings() The first warning reported by calls on this Statement is returned.
void	setCursorName(String name) setCursorname defines the SQL cursor name that will be used by subsequent Statement execute methods.
void	setEscapeProcessing(boolean enable) If escape scanning is on (the default), the driver will do escape substitution before sending the SQL to the database.
void	setFetchDirection(int direction) JDBC 2.0 Give a hint as to the direction in which the rows in a result set will be processed.
void	setFetchSize(int rows) JDBC 2.0 Give the JDBC driver a hint as to the number of rows that should be fetched from the database when more rows are needed.
void	setMaxFieldSize(int max) The maxFieldSize limit (in bytes) is set to limit the size of data that can be returned for any column value; it only applies to BINARY, VARBINARY, LONGVARBINARY, CHAR, VARCHAR, and LONGVARCHAR fields.
void	setMaxRows(int max) The maxRows limit is set to limit the number of rows that any ResultSet can contain.
void	setQueryTimeout(int seconds) The queryTimeout limit is the number of seconds the driver will wait for a Statement to execute.

Method Detail

executeQuery

public ResultSet executeQuery(String sql)
                       throws SQLException

Execute a SQL statement that returns a single ResultSet.

Parameters:: sql - typically this is a static SQL SELECT statement
Returns:: a ResultSet that contains the data produced by the query; never null
Throws:: SQLException - if a database-access error occurs.

executeUpdate

public int executeUpdate(String sql)
                  throws SQLException

Execute a SQL INSERT, UPDATE or DELETE statement. In addition, SQL statements that return nothing such as SQL DDL statements can be executed.

Parameters:: sql - a SQL INSERT, UPDATE or DELETE statement or a SQL statement that returns nothing
Returns:: either the row count for INSERT, UPDATE or DELETE or 0 for SQL statements that return nothing
Throws:: SQLException - if a database-access error occurs.

close

public void close()
           throws SQLException

In many cases, it is desirable to immediately release a Statements's database and JDBC resources instead of waiting for this to happen when it is automatically closed; the close method provides this immediate release.

Note: A Statement is automatically closed when it is garbage collected. When a Statement is closed, its current ResultSet, if one exists, is also closed.

Throws:: SQLException - if a database-access error occurs.

getMaxFieldSize

public int getMaxFieldSize()
                    throws SQLException

The maxFieldSize limit (in bytes) is the maximum amount of data returned for any column value; it only applies to BINARY, VARBINARY, LONGVARBINARY, CHAR, VARCHAR, and LONGVARCHAR columns. If the limit is exceeded, the excess data is silently discarded.

Returns:: the current max column size limit; zero means unlimited
Throws:: SQLException - if a database-access error occurs.

setMaxFieldSize

public void setMaxFieldSize(int max)
                     throws SQLException

The maxFieldSize limit (in bytes) is set to limit the size of data that can be returned for any column value; it only applies 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.

Parameters:: max - the new max column size limit; zero means unlimited
Throws:: SQLException - if a database-access error occurs.

getMaxRows

public int getMaxRows()
               throws SQLException

The maxRows limit is the maximum number of rows that a ResultSet can contain. If the limit is exceeded, the excess rows are silently dropped.

Returns:: the current max row limit; zero means unlimited
Throws:: SQLException - if a database-access error occurs.

setMaxRows

public void setMaxRows(int max)
                throws SQLException

The maxRows limit is set to limit the number of rows that any ResultSet can contain. If the limit is exceeded, the excess rows are silently dropped.

Parameters:: max - the new max rows limit; zero means unlimited
Throws:: SQLException - if a database-access error occurs.

setEscapeProcessing

public void setEscapeProcessing(boolean enable)
                         throws SQLException

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 like have no affect.

Parameters:: enable - true to enable; false to disable
Throws:: SQLException - if a database-access error occurs.

getQueryTimeout

public int getQueryTimeout()
                    throws SQLException

The queryTimeout limit is the number of seconds the driver will wait for a Statement to execute. If the limit is exceeded, a SQLException is thrown.

Returns:: the current query timeout limit in seconds; zero means unlimited
Throws:: SQLException - if a database-access error occurs.

setQueryTimeout

public void setQueryTimeout(int seconds)
                     throws SQLException

The queryTimeout limit is the number of seconds the driver will wait for a Statement to execute. If the limit is exceeded, a SQLException is thrown.

Parameters:: seconds - the new query timeout limit in seconds; zero means unlimited
Throws:: SQLException - if a database-access error occurs.

cancel

public void cancel()
            throws SQLException

Cancel can be used by one thread to cancel a statement that is being executed by another thread.

Throws:: SQLException - if a database-access error occurs.

getWarnings

public SQLWarning getWarnings()
                       throws SQLException

The first warning reported by calls on this Statement is returned. A Statment's execute methods clear its SQLWarning chain. Subsequent Statement warnings will be chained to this SQLWarning.

The warning chain is automatically cleared each time a statement is (re)executed.

Note: If you are processing a ResultSet then any warnings associated with ResultSet reads will be chained on the ResultSet object.

Returns:: the first SQLWarning or null
Throws:: SQLException - if a database-access error occurs.

clearWarnings

public void clearWarnings()
                   throws SQLException

After this call, getWarnings returns null until a new warning is reported for this Statement.

Throws:: SQLException - if a database-access error occurs.

setCursorName

public void setCursorName(String name)
                   throws SQLException

setCursorname defines the SQL cursor name that will be used by subsequent Statement execute methods. This name can then be used in SQL positioned update/delete statements to identify the current row in the ResultSet 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 update, the cursor's select statement should be of the form 'select for update ...'. If the 'for update' clause is omitted the positioned updates may fail.

Note: By definition, positioned update/delete execution must be done by a different Statement than the one which generated the ResultSet being used for positioning. Also, cursor names must be unique within a Connection.

Parameters:: name - the new cursor name.
Throws:: SQLException - if a database-access error occurs.

execute

public boolean execute(String sql)
                throws SQLException

Execute a 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're executing a stored procedure that you know may return multiple results, or unless you're dynamically executing an unknown SQL string. The "execute", "getMoreResults", "getResultSet" and "getUpdateCount" methods let you navigate through multiple results. The "execute" method executes a SQL statement and indicates the form of the first result. You can then use getResultSet or getUpdateCount to retrieve the result, and getMoreResults to move to any subsequent result(s).

Parameters:: sql - any SQL statement
Returns:: true if the next result is a ResultSet; false if it is an update count or there are no more results
Throws:: SQLException - if a database-access error occurs.
See Also:: getResultSet(), getUpdateCount(), getMoreResults()

getResultSet

public ResultSet getResultSet()
                       throws SQLException

getResultSet returns the current result as a ResultSet. It should only be called once per result.

Returns:: the current result as a ResultSet; null if the result is an update count or there are no more results
Throws:: SQLException - if a database-access error occurs.
See Also:: execute(java.lang.String)

getUpdateCount

public int getUpdateCount()
                   throws SQLException

getUpdateCount returns the current result as an update count; if the result is a ResultSet or there are no more results, -1 is returned. It should only be called once per result.

Returns:: the current result as an update count; -1 if it is a ResultSet or there are no more results
Throws:: SQLException - if a database-access error occurs.
See Also:: execute(java.lang.String)

getMoreResults

public boolean getMoreResults()
                       throws SQLException

getMoreResults moves to a Statement's next result. It returns true if this result is a ResultSet. getMoreResults also implicitly closes any current ResultSet obtained with getResultSet. There are no more results when (!getMoreResults() && (getUpdateCount() == -1)

Returns:: true if the next result is a ResultSet; false if it is an update count or there are no more results
Throws:: SQLException - if a database-access error occurs.
See Also:: execute(java.lang.String)

setFetchDirection

public void setFetchDirection(int direction)
                       throws SQLException

JDBC 2.0 Give 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.

Parameters:: direction - the initial direction for processing rows
Throws:: SQLException - if a database-access error occurs or direction is not one of ResultSet.FETCH_FORWARD, ResultSet.FETCH_REVERSE, or ResultSet.FETCH_UNKNOWN

getFetchDirection

public int getFetchDirection()
                      throws SQLException

JDBC 2.0 Determine the fetch direction.

Returns:: the default fetch direction
Throws:: SQLException - if a database-access error occurs

setFetchSize

public void setFetchSize(int rows)
                  throws SQLException

JDBC 2.0 Give 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 only affects result sets created using this statement. If the value specified is zero, then the hint is ignored. The default value is zero.

Parameters:: rows - the number of rows to fetch
Throws:: SQLException - if a database-access error occurs, or the condition 0 <= rows <= this.getMaxRows() is not satisfied.

getFetchSize

public int getFetchSize()
                 throws SQLException

JDBC 2.0 Determine the default fetch size.

getResultSetConcurrency

public int getResultSetConcurrency()
                            throws SQLException

JDBC 2.0 Determine the result set concurrency.

getResultSetType

public int getResultSetType()
                     throws SQLException

JDBC 2.0 Determine the result set type.

addBatch

public void addBatch(String sql)
              throws SQLException

JDBC 2.0 Adds a SQL command to the current batch of commmands for the statement. This method is optional.

Parameters:: sql - typically this is a static SQL INSERT or UPDATE statement
Throws:: SQLException - if a database-access error occurs, or the driver does not support batch statements

clearBatch

public void clearBatch()
                throws SQLException

JDBC 2.0 Make the set of commands in the current batch empty. This method is optional.

Throws:: SQLException - if a database-access error occurs, or the driver does not support batch statements

executeBatch

public int[] executeBatch()
                   throws SQLException

JDBC 2.0 Submit a batch of commands to the database for execution. This method is optional.

Returns:: an array of update counts containing one element for each command in the batch. The array is ordered according to the order in which commands were inserted into the batch
Throws:: SQLException - if a database-access error occurs, or the driver does not support batch statements

getConnection

public Connection getConnection()
                         throws SQLException

JDBC 2.0 Return the Connection that produced the Statement.