ModSQL
Class Update

java.lang.Object
  |
  +--ModSQL.Update

All Implemented Interfaces:

Query

final class Update

extends Object

implements Query

Update will parse and execute an SQL UPDATE query.

Author:

chris.studholme@utoronto.ca

Field Summary

private int[]	column_index Array of indices of columns to update (set by optimize).
private int[]	column_type Array of column types (set by optimize).
private TableReader	reader Reader used to fetch rows (set by optimize).
private String[]	set_column Array of column names to update.
private Function[]	set_value New values for columns.
private DatabaseTable	table Database table to update (set by optimize).
protected DatabaseManager	tablemanager Table manager used to open tables.
private String	tablename Name of table.
private Function	where Where clause used to choose rows.

Constructor Summary

protected

Update(StreamTokenizer tokenizer, DatabaseManager manager) Contructor to parse query.

Method Summary

void	close() Close query and free resources in use.
int	execute() Execute the query.
void	optimize() Optimize query.
private void	ParseUpdate(StreamTokenizer tokenizer) Parse update query of the form: UPDATE tablename SET columns [ WHERE condition ]
String	toString() Returns human-readable string version of query (with surrounding brackets).
String	toString(boolean with_brackets) Returns human-readable string version of query.

Methods inherited from class java.lang.Object

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

Field Detail

tablename

private String tablename

Name of table.

set_column

private String[] set_column

Array of column names to update.

set_value

private Function[] set_value

New values for columns.

where

private Function where

Where clause used to choose rows.

reader

private TableReader reader

Reader used to fetch rows (set by optimize).

table

private DatabaseTable table

Database table to update (set by optimize).

column_index

private int[] column_index

Array of indices of columns to update (set by optimize).

column_type

private int[] column_type

Array of column types (set by optimize).

tablemanager

protected transient DatabaseManager tablemanager

Table manager used to open tables.

Constructor Detail

Update

protected Update(StreamTokenizer tokenizer,
                 DatabaseManager manager)
          throws SQLException,
                 IOException

Contructor to parse query.

Parameters:

tokenizer - StreamTokenizer that SQL tokens should be read from

manager - manager to use when looking up tables

Throws:

SQLException - if an error occurs

IOException - if there is a problem reading the query

Method Detail

close

public void close()

Close query and free resources in use.

Specified by:

close in interface Query

Following copied from interface: ModSQL.Query

Throws:

SQLException - if an error occurs

toString

public String toString()

Returns human-readable string version of query (with surrounding brackets).

Overrides:

toString in class Object

Returns:

String representation of query

toString

public String toString(boolean with_brackets)

Returns human-readable string version of query.

Specified by:

toString in interface Query

Parameters:

with_brackets - true to include surrounding brackets

Returns:

String representation of query

ParseUpdate

private void ParseUpdate(StreamTokenizer tokenizer)
                  throws SQLException,
                         IOException

Parse update query of the form:

UPDATE tablename SET columns [ WHERE condition ]

Parameters:

tokenizer - StreamTokenizer that SQL tokens should be read from

Throws:

SQLException - if an error occurs

IOException - if there is a problem reading the query

optimize

public void optimize()
              throws SQLException

Optimize query.

Specified by:

optimize in interface Query

Throws:

SQLException - if an error occurs

execute

public int execute()
            throws SQLException

Execute the query.

Specified by:

execute in interface Query

Returns:

number of rows updated

Throws:

SQLException - if an error occurs