ACTIONSCRIPT 3 Developer’s Guide en

ACTIONSCRIPT 3.0 DEVELOPER’S GUIDE
Working with local SQL databases in AIR
identifier value as the foreign key column value just as you would with an explicitly declared INTEGER PRIMARY KEY
column. In that sense, if you are using an arbitrary primary key rather than a natural key, and as long as you don’t mind
the runtime generating the primary key value for you, it makes little difference whether you use an INTEGER PRIMARY
KEY column or the system-generated row identifier as a table’s primary key for defining a foreign key relationship with
between two tables.
For more information about primary keys and generated row identifiers, see “SQL support in local databases” on
page 1093.
Changing or deleting data
Adobe AIR 1.0 and later
The process for executing other data manipulation operations is identical to the process used to execute a SQL SELECT
or INSERT statement, as described in “Working with SQL statements” on page 728. Simply substitute a different SQL
statement in the SQLStatement instance’s text property:
To change existing data in a table, use an UPDATE statement.
To delete one or more rows of data from a table, use a DELETE statement.
For descriptions of these statements, see “SQL support in local databases” on page 1093.
Working with multiple databases
Adobe AIR 1.0 and later
Use the SQLConnection.attach() method to open a connection to an additional database on a SQLConnection
instance that already has an open database. You give the attached database a name using the name parameter in the
attach() method call. When writing statements to manipulate that database, you can then use that name in a prefix
(using the form database-name.table-name) to qualify any table names in your SQL statements, indicating to the
runtime that the table can be found in the named database.
You can execute a single SQL statement that includes tables from multiple databases that are connected to the same
SQLConnection instance. If a transaction is created on the SQLConnection instance, that transaction applies to all SQL
statements that are executed using the SQLConnection instance. This is true regardless of which attached database the
statement runs on.
Alternatively, you can also create multiple SQLConnection instances in an application, each of which is connected to
one or multiple databases. However, if you do use multiple connections to the same database keep in mind that a
database transaction isn’t shared across SQLConnection instances. Consequently, if you connect to the same database
file using multiple SQLConnection instances, you can’t rely on both connections’ data changes being applied in the
expected manner. For example, if two UPDATE or DELETE statements are run against the same database through
different SQLConnection instances, and an application error occurs after one operation takes place, the database data
could be left in an intermediate state that would not be reversible and might affect the integrity of the database (and
consequently the application).
Last updated 6/6/2012
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