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com.uwyn.rife.database
Class DbStatement

java.lang.Object
  extended by com.uwyn.rife.database.DbStatement
All Implemented Interfaces:
Cloneable
Direct Known Subclasses:
DbPreparedStatement
public class DbStatement
extends Object
implements Cloneable

Provides a wrapper around the regular JDBC Statement class. It can only be instantiated by calling the createStatement method on an existing DbConnection instance.

This class hooks into the database connection pool and cleans up as much as possible in case of errors. The thrown DatabaseException exceptions should thus only be used for error reporting and not for releasing resources used by the framework.

The execute and executeQuery methods store their result set in the executing DbStatement instance. It's recommended to use the DbQueryManager's fetch method to process the result set. If needed, one can also use the getResultSet method to manually process the results through plain JDBC. However, when exceptions are thrown during this procedure, it's also the responsability of the user to correctly clean up all resources.

Additional methods have been implemented to facilitate the retrieval of queries which return only a single field and to easily check if a query returned any result rows.

Since:
1.0
Version:
$Revision: 3648 $
Author:
Geert Bevin (gbevin[remove] at uwyn dot com)
See Also:
executeQuery(String), execute(String), execute(String, int), execute(String, int[]), execute(String, String[]), getResultSet(), DbConnection.createStatement(), DbQueryManager.fetch(ResultSet, DbRowProcessor), ResultSet, Statement

Method Summary
 void addBatch(String sql)
          Adds the given SQL command to the current list of commmands for this Statement object.
 void cancel()
          Cancels this DbStatement object if both the DBMS and driver support aborting a SQL statement.
 void clearBatch()
          Empties this Statement object's current list of SQL commands.
 void clearWarnings()
          Clears all the warnings reported on this DbStatement object.
 Object clone()
          Simply clones the instance with the default clone method.
 void close()
          Releases this DbStatement object's database and JDBC resources immediately instead of waiting for this to happen when it is automatically closed.
 boolean execute(String sql)
          Executes the given SQL statement, which may return multiple results.
 boolean execute(String sql, int autoGeneratedKeys)
          Executes the given SQL statement, which may return multiple results, and signals the driver that any auto-generated keys should be made available for retrieval.
 boolean execute(String sql, int[] columnIndexes)
          Executes the given SQL statement, which may return multiple results, and signals the driver that the auto-generated keys indicated in the given array should be made available for retrieval.
 boolean execute(String sql, String[] columnNames)
          Executes the given SQL statement, which may return multiple results, and signals the driver that the auto-generated keys indicated in the given array should be made available for retrieval.
 int[] executeBatch()
          Submits a batch of commands to the database for execution and if all commands execute successfully, returns an array of update counts.
 void executeQuery(ReadQuery query)
          Executes the given Query builder's SQL statement.
 void executeQuery(String sql)
          Executes the given SQL statement.
 int executeUpdate(Query query)
          Executes the given Query builder's SQL statement, which may be an INSERT, UPDATE, or DELETE statement or a SQL statement that returns nothing, such as an SQL DDL statement.
 int executeUpdate(String sql)
          Executes the given SQL statement, which may be an INSERT, UPDATE, or DELETE statement or an SQL statement that returns nothing, such as an SQL DDL statement.
protected  void finalize()
          Ensures that this DbStatement is correctly closed when it's garbage collected.
 DbConnection getConnection()
          Returns the DbConnection object from which this DbStatement object has been instantiated.
 int getFetchDirection()
          Retrieves the direction for fetching rows from database tables that is the default for result sets generated from this DbStatement object.
 int getFetchSize()
          Retrieves the number of result set rows that is the default fetch size for ResultSet objects generated from this DbStatement object.
 int getFirstGeneratedIntKey()
          Retrieves the first auto-generated key created as a result of executing this DbStatement object as an integer.
 DbResultSet getGeneratedKeys()
          Retrieves any auto-generated keys created as a result of executing this DbStatement object.
 int getMaxFieldSize()
          Retrieves the maximum number of bytes that can be returned for character and binary column values in a ResultSet object produced by this Statement object.
 int getMaxRows()
          Retrieves the maximum number of rows that a ResultSet object produced by this DbStatement object can contain.
 boolean getMoreResults()
          Moves to this DbStatement object's next result, returns true if it is a ResultSet object, and implicitly closes any current ResultSet object(s) obtained with the method getResultSet.
 boolean getMoreResults(int current)
          Moves to this DbStatement object's next result, deals with any current ResultSet object(s) according to the instructions specified by the given flag, and returns true if the next result is a ResultSet object.
 int getQueryTimeout()
          Retrieves the number of seconds the driver will wait for a DbStatement object to execute.
 DbResultSet getResultSet()
          Retrieves the current result as a ResultSet object.
 int getResultSetConcurrency()
          Retrieves the result set concurrency for ResultSet objects generated by this DbStatement object.
 int getResultSetHoldability()
          Retrieves the result set holdability for ResultSet objects generated by this DbStatement object.
 int getResultSetType()
          Retrieves the result set type for ResultSet objects generated by this DbStatement object.
 int getUpdateCount()
          Retrieves the current result as an update count; if the result is a ResultSet object or there are no more results, -1 is returned.
 SQLWarning getWarnings()
          Retrieves the first warning reported by calls on this Statement object.
protected  void handleException()
          Performs the cleanup logic in case an exeception is thrown during execution.
protected  void outputTrace(long start, String sql)
           
 void setFetchDirection(int direction)
          Gives the driver a hint as to the direction in which rows will be processed in ResultSet objects created using this DbStatement object.
 void setFetchSize(int rows)
          Gives 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)
          Sets the limit for the maximum number of bytes in a ResultSet column storing character or binary values to the given number of bytes.
 void setMaxRows(int max)
          Sets the limit for the maximum number of rows that any ResultSet object can contain to the given number.
 void setQueryTimeout(int max)
          Sets the number of seconds the driver will wait for a DbStatement object to execute to the given number of seconds.
protected  void setResultset(ResultSet resultSet)
          Set the current ResultSet object and cleans up the previous ResultSet object automatically.
protected  long startTrace()
           
protected  void traceBatch(String sql)
           
 boolean wasNull()
          Reports whether the last column read had a value of SQL NULL.
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Method Detail

addBatch

public void addBatch(String sql)
              throws DatabaseException
Adds the given SQL command to the current list of commmands for this Statement object. The commands in this list can be executed as a batch by calling the method executeBatch.

If an exception is thrown, this DbStatement is automatically closed and an ongoing transaction will be automatically rolled back if it belongs to the executing thread.

Parameters:
sql - typically this is a static SQL INSERT or UPDATE statement
Throws:
DatabaseException - if a database access error occurs, or the driver does not support batch updates
Since:
1.0
See Also:
executeBatch()

cancel

public void cancel()
            throws DatabaseException
Cancels this DbStatement object if both the DBMS and driver support aborting a SQL statement. This method can be used by one thread to cancel a statement that is being executed by another thread.

If an exception is thrown, this DbStatement is automatically closed and an ongoing transaction will be automatically rolled back if it belongs to the executing thread.

Throws:
DatabaseException - if a database access error occurs
Since:
1.0

clearBatch

public void clearBatch()
                throws DatabaseException
Empties this Statement object's current list of SQL commands.

If an exception is thrown, this DbStatement is automatically closed and an ongoing transaction will be automatically rolled back if it belongs to the executing thread.

Throws:
DatabaseException - if a database access error occurs or the driver does not support batch updates
Since:
1.0
See Also:
addBatch(java.lang.String)

clearWarnings

public void clearWarnings()
                   throws DatabaseException
Clears all the warnings reported on this DbStatement object. After a call to this method, the method getWarnings will return null until a new warning is reported for this DbStatement object.

If an exception is thrown, this DbStatement is automatically closed and an ongoing transaction will be automatically rolled back if it belongs to the executing thread.

Throws:
DatabaseException - if a database access error occurs
Since:
1.0

close

public void close()
           throws DatabaseException
Releases this DbStatement 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.

Calling the method close on a DbStatement object that is already closed has no effect.

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

Throws:
DatabaseException - if a database access error occurs
Since:
1.0

startTrace

protected long startTrace()

outputTrace

protected void outputTrace(long start,
                           String sql)

traceBatch

protected void traceBatch(String sql)

execute

public boolean execute(String sql)
                throws DatabaseException
Executes the given SQL statement, which may return multiple results. In 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 execute method executes a SQL statement and indicates the form of the first result. You must then use the methods getResultSet or getUpdateCount to retrieve the result, and getMoreResults to move to any subsequent result(s).

If an exception is thrown, this DbStatement is automatically closed and an ongoing transaction will be automatically rolled back if it belongs to the executing thread.

Parameters:
sql - any SQL statement
Returns:
true if the first result is a ResultSet object; or

false if it is an update count or there are no results

Throws:
DatabaseException - if a database access error occurs
Since:
1.0
See Also:
getResultSet(), getUpdateCount(), getMoreResults()

execute

public boolean execute(String sql,
                       int autoGeneratedKeys)
                throws DatabaseException
Executes the given SQL statement, which may return multiple results, and signals the driver that any auto-generated keys should be made available for retrieval. The driver will ignore this signal if the SQL statement is not an INSERT statement.

In 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 execute method executes a SQL statement and indicates the form of the first result. You must then use the methods getResultSet or getUpdateCount to retrieve the result, and getMoreResults to move to any subsequent result(s).

If an exception is thrown, this DbStatement is automatically closed and an ongoing transaction will be automatically rolled back if it belongs to the executing thread.

Parameters:
sql - any SQL statement
autoGeneratedKeys - a constant indicating whether auto-generated keys should be made available for retrieval using the method getGeneratedKeys; one of the following constants: Statement.RETURN_GENERATED_KEYS or Statement.NO_GENERATED_KEYS
Returns:
true if the first result is a ResultSet object; or

false if it is an update count or there are no results

Throws:
DatabaseException - if a database access error occurs
Since:
1.0
See Also:
Statement, getResultSet(), getUpdateCount(), getMoreResults(), getGeneratedKeys()

execute

public boolean execute(String sql,
                       int[] columnIndexes)
                throws DatabaseException
Executes the given SQL statement, which may return multiple results, and signals the driver that the auto-generated keys indicated in the given array should be made available for retrieval. This array contains the indexes of the columns in the target table that contain the auto-generated keys that should be made available. The driver will ignore the array if the given SQL statement is not an INSERT statement.

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 execute method executes a SQL statement and indicates the form of the first result. You must then use the methods getResultSet or getUpdateCount to retrieve the result, and getMoreResults to move to any subsequent result(s).

If an exception is thrown, this DbStatement is automatically closed and an ongoing transaction will be automatically rolled back if it belongs to the executing thread.

Parameters:
sql - any SQL statement
columnIndexes - an array of the indexes of the columns in the inserted row that should be made available for retrieval by a call to the method getGeneratedKeys
Returns:
true if the first result is a ResultSet object; or

false if it is an update count or there are no results

Throws:
DatabaseException - if a database access error occurs
Since:
1.0
See Also:
getResultSet(), getUpdateCount(), getMoreResults()

execute

public boolean execute(String sql,
                       String[] columnNames)
                throws DatabaseException
Executes the given SQL statement, which may return multiple results, and signals the driver that the auto-generated keys indicated in the given array should be made available for retrieval. This array contains the names of the columns in the target table that contain the auto-generated keys that should be made available. The driver will ignore the array if the given SQL statement is not an INSERT statement.

In 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 execute method executes a SQL statement and indicates the form of the first result. You must then use the methods getResultSet or getUpdateCount to retrieve the result, and getMoreResults to move to any subsequent result(s).

If an exception is thrown, this DbStatement is automatically closed and an ongoing transaction will be automatically rolled back if it belongs to the executing thread.

Parameters:
sql - any SQL statement
columnNames - an array of the names of the columns in the inserted row that should be made available for retrieval by a call to the method getGeneratedKeys
Returns:
true if the next result is a ResultSet object; or

false if it is an update count or there are no more results

Throws:
DatabaseException - if a database access error occurs
Since:
1.0
See Also:
getResultSet(), getUpdateCount(), getMoreResults(), getGeneratedKeys()

executeBatch

public int[] executeBatch()
                   throws DatabaseException
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:
  1. 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
  2. A value of SUCCESS_NO_INFO -- 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:

  3. A value of EXECUTE_FAILED -- 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.

If an exception is thrown, this DbStatement is automatically closed and an ongoing transaction will be automatically rolled back if it belongs to the executing thread.

Returns:
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.
Throws:
DatabaseException - if a database access error occurs or the driver does not support batch statements. The cause is a BatchUpdateException (a subclass of SQLException) if one of the commands sent to the database fails to execute properly or attempts to return a result set.
Since:
1.0

executeQuery

public void executeQuery(String sql)
                  throws DatabaseException
Executes the given SQL statement. The returned ResultSet object is stored and can be retrieved with the getResultSet method.

If an exception is thrown, this DbStatement is automatically closed and an ongoing transaction will be automatically rolled back if it belongs to the executing thread.

Parameters:
sql - a SQL statement to be sent to the database, typically a static SQL SELECT statement
Throws:
DatabaseException - if a database access error occurs or the given SQL statement produces anything other than a single ResultSet object
Since:
1.0
See Also:
getResultSet()

executeQuery

public void executeQuery(ReadQuery query)
                  throws DatabaseException
Executes the given Query builder's SQL statement. The returned ResultSet object is stored and can be retrieved with the getResultSet method.

If an exception is thrown, this DbStatement is automatically closed and an ongoing transaction will be automatically rolled back if it belongs to the executing thread.

Parameters:
query - a Query builder instance which provides a SQL statement that queries the database
Throws:
DatabaseException - if a database access error occurs or the given SQL statement produces anything other than a single ResultSet object
Since:
1.0
See Also:
getResultSet()

executeUpdate

public int executeUpdate(String sql)
                  throws DatabaseException
Executes the given SQL statement, which may be an INSERT, UPDATE, or DELETE statement or an SQL statement that returns nothing, such as an SQL DDL statement.

If an exception is thrown, this DbStatement is automatically closed and an ongoing transaction will be automatically rolled back if it belongs to the executing thread.

Parameters:
sql - an SQL INSERT, UPDATE or DELETE statement or a SQL statement that returns nothing
Returns:
the row count for INSERT, UPDATE or DELETE statements; or

0 for SQL statements that return nothing

Throws:
DatabaseException - if a database access error occurs or the given SQL statement produces a ResultSet object
Since:
1.0

executeUpdate

public int executeUpdate(Query query)
                  throws DatabaseException
Executes the given Query builder's SQL statement, which may be an INSERT, UPDATE, or DELETE statement or a SQL statement that returns nothing, such as an SQL DDL statement.

If an exception is thrown, this DbStatement is automatically closed and an ongoing transaction will be automatically rolled back if it belongs to the executing thread.

Parameters:
query - a Query builder instance which provides a SQL statement that modifies the database
Returns:
the row count for INSERT, UPDATE or DELETE statements; or

0 for SQL statements that return nothing

Throws:
DatabaseException - if a database access error occurs or the given SQL statement produces a ResultSet object
Since:
1.0

getFetchDirection

public int getFetchDirection()
                      throws DatabaseException
Retrieves the direction for fetching rows from database tables that is the default for result sets generated from this DbStatement object. If this DbStatement object has not set a fetch direction by calling the method setFetchDirection, the return value is implementation-specific.

If an exception is thrown, this DbStatement is automatically closed and an ongoing transaction will be automatically rolled back if it belongs to the executing thread.

Returns:
the default fetch direction for result sets generated from this DbStatement object
Throws:
DatabaseException - if a database access error occurs
Since:
1.0
See Also:
setFetchDirection(int)

getFetchSize

public int getFetchSize()
                 throws DatabaseException
Retrieves the number of result set rows that is the default fetch size for ResultSet objects generated from this DbStatement object. If this DbStatement object has not set a fetch size by calling the method setFetchSize, the return value is implementation-specific.

If an exception is thrown, this DbStatement is automatically closed and an ongoing transaction will be automatically rolled back if it belongs to the executing thread.

Returns:
the default fetch size for result sets generated from this DbStatement object
Throws:
DatabaseException - if a database access error occurs
Since:
1.0
See Also:
setFetchSize(int)

getGeneratedKeys

public DbResultSet getGeneratedKeys()
                             throws DatabaseException
Retrieves any auto-generated keys created as a result of executing this DbStatement object. If this DbStatement object did not generate any keys, an empty DbResultSet object is returned.

If an exception is thrown, this DbStatement is automatically closed and an ongoing transaction will be automatically rolled back if it belongs to the executing thread.

Returns:
a DbResultSet object containing the auto-generated key(s) generated by the execution of this DbStatement object
Throws:
DatabaseException - if a database access error occurs
Since:
1.0

getFirstGeneratedIntKey

public int getFirstGeneratedIntKey()
                            throws DatabaseException
Retrieves the first auto-generated key created as a result of executing this DbStatement object as an integer. If this DbStatement object did not generate any keys, a exception is thrown.

If an exception is thrown, this DbStatement is automatically closed and an ongoing transaction will be automatically rolled back if it belongs to the executing thread.

Returns:
the first auto-generated key as an integer
Throws:
DatabaseException - if a database access error occurs
Since:
1.0

getMaxFieldSize

public int getMaxFieldSize()
                    throws DatabaseException
Retrieves the maximum number of bytes that can be returned for character and binary column values in a ResultSet object produced by this Statement object. This limit applies only to BINARY, VARBINARY, LONGVARBINARY, CHAR, VARCHAR, and LONGVARCHAR columns. If the limit is exceeded, the excess data is silently discarded.

If an exception is thrown, this DbStatement is automatically closed and an ongoing transaction will be automatically rolled back if it belongs to the executing thread.

Returns:
the current column size limit for columns storing character and binary values; or

0 if there's no limit

Throws:
DatabaseException - if a database access error occurs
Since:
1.0
See Also:
setMaxFieldSize(int)

getMaxRows

public int getMaxRows()
               throws DatabaseException
Retrieves the maximum number of rows that a ResultSet object produced by this DbStatement object can contain. If this limit is exceeded, the excess rows are silently dropped.

If an exception is thrown, this DbStatement is automatically closed and an ongoing transaction will be automatically rolled back if it belongs to the executing thread.

Returns:
the current maximum number of rows for a ResultSet object produced by this Statement object; or

0 if there's no limit

Throws:
DatabaseException - if a database access error occurs
Since:
1.0
See Also:
setMaxRows(int)

getMoreResults

public boolean getMoreResults()
                       throws DatabaseException
Moves to this DbStatement object's next result, returns true if it is a ResultSet object, and implicitly closes any current ResultSet object(s) obtained with the method getResultSet.

There are no more results when the following is true: 

 (!getMoreResults() && (getUpdateCount() == -1)

If an exception is thrown, this DbStatement is automatically closed and an ongoing transaction will be automatically rolled back if it belongs to the executing thread.

Returns:
true if the next result is a ResultSet object; or

false if it is an update count or there are no more results

Throws:
DatabaseException - if a database access error occurs
Since:
1.0
See Also:
execute(java.lang.String)

getMoreResults

public boolean getMoreResults(int current)
                       throws DatabaseException
Moves to this DbStatement object's next result, deals with any current ResultSet object(s) according to the instructions specified by the given flag, and returns true if the next result is a ResultSet object.

There are no more results when the following is true: 

          (!getMoreResults() && (getUpdateCount() == -1)

If an exception is thrown, this DbStatement is automatically closed and an ongoing transaction will be automatically rolled back if it belongs to the executing thread.

Parameters:
current - one of the following Statement constants indicating what should happen to current ResultSet objects obtained using the method getResultSet: CLOSE_CURRENT_RESULT, KEEP_CURRENT_RESULT, or CLOSE_ALL_RESULTS
Returns:
true if the next result is a ResultSet object; or

false if it is an update count or there are no more results

Throws:
DatabaseException - if a database access error occurs
Since:
1.0
See Also:
Statement, execute(java.lang.String)

getQueryTimeout

public int getQueryTimeout()
                    throws DatabaseException
Retrieves the number of seconds the driver will wait for a DbStatement object to execute. If the limit is exceeded, a DatabaseException is thrown.

If an exception is thrown, this DbStatement is automatically closed and an ongoing transaction will be automatically rolled back if it belongs to the executing thread.

Returns:
the current query timeout limit in seconds; or

0 if there's no limit

Throws:
DatabaseException - if a database access error occurs
Since:
1.0
See Also:
setQueryTimeout(int)

wasNull

public boolean wasNull()
                throws DatabaseException
Reports whether the last column read had a value of SQL NULL. Note that you must first call one of the getter methods on a column to try to read its value and then call the method wasNull to see if the value read was SQL NULL.

If an exception is thrown, this DbStatement is automatically closed and an ongoing transaction will be automatically rolled back if it belongs to the executing thread.

Returns:
true if the last column value read was SQL NULL; or

false otherwise

Throws:
DatabaseException - if a database access error occurs
Since:
1.0

getResultSetConcurrency

public int getResultSetConcurrency()
                            throws DatabaseException
Retrieves the result set concurrency for ResultSet objects generated by this DbStatement object.

If an exception is thrown, this DbStatement is automatically closed and an ongoing transaction will be automatically rolled back if it belongs to the executing thread.

Returns:
either ResultSet.CONCUR_READ_ONLY or ResultSet.CONCUR_UPDATABLE
Throws:
DatabaseException - if a database access error occurs
Since:
1.0
See Also:
ResultSet

getResultSetHoldability

public int getResultSetHoldability()
                            throws DatabaseException
Retrieves the result set holdability for ResultSet objects generated by this DbStatement object.

If an exception is thrown, this DbStatement is automatically closed and an ongoing transaction will be automatically rolled back if it belongs to the executing thread.

Returns:
either ResultSet.HOLD_CURSORS_OVER_COMMIT or ResultSet.CLOSE_CURSORS_AT_COMMIT
Throws:
DatabaseException - if a database access error occurs
Since:
1.0
See Also:
ResultSet

getResultSetType

public int getResultSetType()
                     throws DatabaseException
Retrieves the result set type for ResultSet objects generated by this DbStatement object.

If an exception is thrown, this DbStatement is automatically closed and an ongoing transaction will be automatically rolled back if it belongs to the executing thread.

Returns:
one of ResultSet.TYPE_FORWARD_ONLY, ResultSet.TYPE_SCROLL_INSENSITIVE, or ResultSet.TYPE_SCROLL_SENSITIVE
Throws:
DatabaseException - if a database access error occurs
Since:
1.0
See Also:
ResultSet

getUpdateCount

public int getUpdateCount()
                   throws DatabaseException
Retrieves 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.

If an exception is thrown, this DbStatement is automatically closed and an ongoing transaction will be automatically rolled back if it belongs to the executing thread.

Returns:
the current result as an update count; or

-1 if the current result is a ResultSet object or there are no more results

Throws:
DatabaseException - if a database access error occurs
Since:
1.0
See Also:
execute(java.lang.String)

getWarnings

public SQLWarning getWarnings()
                       throws DatabaseException
Retrieves the first warning reported by calls on this Statement object. Subsequent DbStatement object warnings will be chained to this SQLWarning object.

The warning chain is automatically cleared each time a statement is (re)executed. This method may not be called on a closed DbStatement object; doing so will cause an SQLException to be thrown.

If an exception is thrown, this DbStatement is automatically closed and an ongoing transaction will be automatically rolled back if it belongs to the executing thread.

Note: If you are processing a ResultSet object, any warnings associated with reads on that ResultSet object will be chained on it rather than on the DbStatement object that produced it.

Returns:
the first SQLWarning object; or

null if there are no warnings

Throws:
DatabaseException - if a database access error occurs or this method is called on a closed statement
Since:
1.0

getResultSet

public DbResultSet getResultSet()
Retrieves the current result as a ResultSet object. This method returns the internally stored result and can be called as many times as wanted, contrary to the regular JDBC counterpart.

Returns:
the current result as a ResultSet object; or

NULL if the result is an update count.

Since:
1.0
See Also:
execute(java.lang.String)

setFetchDirection

public void setFetchDirection(int direction)
                       throws DatabaseException
Gives the driver a hint as to the direction in which rows will be processed in ResultSet objects created using this DbStatement object. The default value is ResultSet.FETCH_FORWARD.

Note that this method sets the default fetch direction for result sets generated by this DbStatement object. Each result set has its own methods for getting and setting its own fetch direction.

If an exception is thrown, this DbStatement is automatically closed and an ongoing transaction will be automatically rolled back if it belongs to the executing thread.

Parameters:
direction - the initial direction for processing rows
Throws:
DatabaseException - if a database access error occurs or the given direction is not one of ResultSet.FETCH_FORWARD, ResultSet.FETCH_REVERSE, or ResultSet.FETCH_UNKNOWN
Since:
1.0
See Also:
getFetchDirection(), ResultSet

setFetchSize

public void setFetchSize(int rows)
                  throws DatabaseException
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.

If an exception is thrown, this DbStatement is automatically closed and an ongoing transaction will be automatically rolled back if it belongs to the executing thread.

Parameters:
rows - the number of rows to fetch
Throws:
DatabaseException - if a database access error occurs, or the condition 0 <= rows <= this.getMaxRows() is not satisfied.
Since:
1.0
See Also:
getFetchSize(), getMaxRows()

setMaxFieldSize

public void setMaxFieldSize(int max)
                     throws DatabaseException
Sets the limit for the maximum number of bytes in a ResultSet column storing character or binary values to the given number of bytes. 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.

If an exception is thrown, this DbStatement is automatically closed and an ongoing transaction will be automatically rolled back if it belongs to the executing thread.

Parameters:
max - the new column size limit in bytes; zero means there is no limit
Throws:
DatabaseException - if a database access error occurs or the condition max >= 0 is not satisfied
Since:
1.0
See Also:
getMaxFieldSize()

setMaxRows

public void setMaxRows(int max)
                throws DatabaseException
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.

If an exception is thrown, this DbStatement is automatically closed and an ongoing transaction will be automatically rolled back if it belongs to the executing thread.

Parameters:
max - the new max rows limit; zero means there is no limit
Throws:
DatabaseException - if a database access error occurs or the condition max >= 0 is not satisfied
Since:
1.0
See Also:
getMaxRows()

setQueryTimeout

public void setQueryTimeout(int max)
                     throws DatabaseException
Sets the number of seconds the driver will wait for a DbStatement object to execute to the given number of seconds. If the limit is exceeded, an DatabaseException is thrown.

Parameters:
max - the new query timeout limit in seconds; zero means there is no limit
Throws:
DatabaseException - if a database access error occurs or the condition seconds >= 0 is not satisfied
Since:
1.0
See Also:
getQueryTimeout()

getConnection

public DbConnection getConnection()
Returns the DbConnection object from which this DbStatement object has been instantiated.

Returns:
the instantiating DbConnection object.
Since:
1.0

setResultset

protected void setResultset(ResultSet resultSet)
                     throws DatabaseException
Set the current ResultSet object and cleans up the previous ResultSet object automatically.

Parameters:
resultSet - the new current ResultSet object
Throws:
DatabaseException - if a database access error occurred.
Since:
1.0

handleException

protected void handleException()
                        throws DatabaseException
Performs the cleanup logic in case an exeception is thrown during execution. The statement will be closed and if a transaction is active, it will be automatically rolled back.

Throws:
DatabaseException - when an error occurs during the cleanup of the connection, or when an error occurs during the roll-back.

finalize

protected void finalize()
                 throws Throwable
Ensures that this DbStatement is correctly closed when it's garbage collected.

Overrides:
finalize in class Object
Throws:
Throwable - if an error occurred during the finalization
Since:
1.0

clone

public Object clone()
Simply clones the instance with the default clone method. This creates a shallow copy of all fields and the clone will in fact just be another reference to the same underlying data. The independence of each cloned instance is consciously not respected since they rely on resources that can't be cloned.

Overrides:
clone in class Object
Since:
1.0
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