ACTIONSCRIPT 3 Developer’s Guide en

ACTIONSCRIPT 3.0 DEVELOPER’S GUIDE
SQL support in local databases
The COLLATE clause following each column name defines a collating sequence used for text values in that column.
The default collation sequence is the collation sequence defined for that column in the CREATE TABLE statement. If
no collation sequence is specified, the BINARY collation sequence is used. For a definition of the COLLATE clause
and collation functions see COLLATE.
There are no arbitrary limits on the number of indices that can be attached to a single table. There are also no limits
on the number of columns in an index.
DROP INDEX
The drop index statement removes an index added with the CREATE INDEX statement. The specified index is
completely removed from the database file. The only way to recover the index is to reenter the appropriate CREATE
INDEX command.
sql-statement ::= DROP INDEX [IF EXISTS] [database-name.] index-name
By default the DROP INDEX statement does not reduce the size of the database file. Empty space in the database is
retained and used in subsequent INSERT operations. To remove free space in the database use the
SQLConnection.clean() method. If the autoClean parameter is set to true when the database is initially created, the
space is freed automatically.
CREATE VIEW
The CREATE VIEW command assigns a name to a pre-defined SELECT statement. This new name can then be used
in a FROM clause of another SELECT statement in place of a table name. Views are commonly used to simplify queries
by combining a complex (and frequently used) set of data into a structure that can be used in other operations.
sql-statement ::= CREATE [TEMP | TEMPORARY] VIEW [IF NOT EXISTS] [database-name.] view-name AS
select-statement
If the TEMP or TEMPORARY keyword occurs in between CREATE and VIEW then the view that is created is only
visible to the SQLConnection instance that opened the database and is automatically deleted when the database is
closed.
If a [database-name] is specified the view is created in the named database (a database that was connected to the
SQLConnection instance using the attach() method, with the specified name argument. It is an error to specify both a
[database-name] and the TEMP keyword unless the [database-name] is temp. If no database name is specified, and the
TEMP keyword is not present, the view is created in the main database (the database that was connected to the
SQLConnection instance using the open() or openAsync() method).
Views are read only. A DELETE, INSERT, or UPDATE statement cannot be used on a view, unless at least one trigger
of the associated type (INSTEAD OF DELETE, INSTEAD OF INSERT, INSTEAD OF UPDATE) is defined. For
information on creating a trigger for a view, see CREATE TRIGGER.
A view is removed from a database using the DROP VIEW statement.
DROP VIEW
The DROP VIEW statement removes a view created by a CREATE VIEW statement.
sql-statement ::= DROP VIEW [IF EXISTS] view-name
The specified view-name is the name of the view to drop. It is removed from the database, but no data in the underlying
tables is modified.
CREATE TRIGGER
The create trigger statement is used to add triggers to the database schema. A trigger is a database operation (the
trigger-action) that is automatically performed when a specified database event (the database-event) occurs.
Last updated 6/6/2012
1101