ACTIONSCRIPT 3 Developer’s Guide en

ACTIONSCRIPT 3.0 DEVELOPER’S GUIDE
SQL support in local databases
ALTER TABLE
The ALTER TABLE command allows the user to rename or add a new column to an existing table. It is not possible
to remove a column from a table.
sql-statement ::= ALTER TABLE [database-name.] table-name alteration
alteration ::= RENAME TO new-table-name
alteration ::= ADD [COLUMN] column-def
The RENAME TO syntax is used to rename the table identified by [database-name.] table-name to new-table-name.
This command cannot be used to move a table between attached databases, only to rename a table within the same
database.
If the table being renamed has triggers or indices, then they remain attached to the table after it has been renamed.
However, if there are any view definitions or statements executed by triggers that refer to the table being renamed, they
are not automatically modified to use the new table name. If a renamed table has associated views or triggers, you must
manually drop and recreate the triggers or view definitions using the new table name.
The ADD [COLUMN] syntax is used to add a new column to an existing table. The new column is always appended
to the end of the list of existing columns. The column-def clause may take any of the forms permissible in a CREATE
TABLE statement, with the following restrictions:
The column may not have a PRIMARY KEY or UNIQUE constraint.
The column may not have a default value of CURRENT_TIME, CURRENT_DATE or CURRENT_TIMESTAMP.
If a NOT NULL constraint is specified, the column must have a default value other than NULL.
The execution time of the ALTER TABLE statement is not affected by the amount of data in the table.
DROP TABLE
The DROP TABLE statement removes a table added with a CREATE TABLE statement. The table with the specified
table-name is the table that's dropped. It is completely removed from the database and the disk file. The table cannot
be recovered. All indices associated with the table are also deleted.
sql-statement ::= DROP TABLE [IF EXISTS] [database-name.] table-name
By default the DROP TABLE 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.
The optional IF EXISTS clause suppresses the error that would normally result if the table does not exist.
CREATE INDEX
The CREATE INDEX command consists of the keywords CREATE INDEX followed by the name of the new index,
the keyword ON, the name of a previously created table that is to be indexed, and a parenthesized list of names of
columns in the table whose values are used for the index key.
sql-statement ::= CREATE [UNIQUE] INDEX [IF NOT EXISTS] [database-name.] index-name
ON table-name ( column-name [, column-name]* )
column-name ::= name [COLLATE collation-name] [ASC | DESC]
Each column name can be followed by ASC or DESC keywords to indicate sort order, but the sort order designation
is ignored by the runtime. Sorting is always done in ascending order.
Last updated 6/6/2012
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