| PATH |
Describes how to insert a row into the database using the adaptor channel's insertRow method.
There are three ways to insert a row into the database with the adaptor sublayer. You can insert using raw SQL using the adaptor channel's evaluateExpression method, the adaptor channel's insertRow method, or a stored procedure.
In this topic we describe how to insert a row using the insertRow method. This method eliminates the overhead associated with snapshots, uniquing, and fault creation. Furthermore, the source code does not depend on the particular database you use. However, you have to work with raw row dictionaries and you are responsible for setting the primary key. This example sets the primary key using the adaptor channel's primaryKeyForNewRowWithEntity method. See the programming topic Generating Primary Key Values for more information about the tradeoffs when generating primary keys.
If you are working with an editing context and inserting using the adaptor sublayer at the same time, EOF does not realize that an object has been inserted. You need to synchronize any enterprise objects with the changes to the database.
To insert a row using the adaptor channel's insertRow method, you need to provide
The following code inserts a row using the adaptor sublayer.
EOAdaptorChannel myAdaptorChannel; // assume exists String modelName = "movies"; String entityName = "Movie"; NSMutableDictionary dict = new NSMutableDictionary(); dict.setObjectForKey ("EOF III: The Multithreading","title"); dict.setObjectForKey ("Action","category"); dict.setObjectForKey (new Integer(90000000),"revenue"); EOModel myModel = EOModelGroup.defaultGroup().modelNamed(modelName); EOEntity myEntity = myModel.entityNamed(entityName); myAdaptorChannel.openChannel(); dict.addEntriesFromDictionary(myAdaptorChannel. // get a primary key primaryKeyForNewRowWithEntity(myEntity)); myAdaptorChannel.insertRow(dict,myEntity); // insert the row myAdaptorChannel.closeChannel();
The code first allocates and initializes a raw row dictionary for the new database row.
The code then finds the EOModel corresponding to the model name in the default model group. The default model group, accessed using EOModelGroup.defaultGroup() is a collection of EOModel objects corresponding to the models in the project's Resources suitcase. If you already have the EOModel, you don't need this step. Next, the code determines the EOEntity corresponding to the given entity name from the EOModel.
Before performing insertRow with the adaptor channel, the code establishes a connection to the database using the openChannel method and determines a primary key for the row. The primaryKeyForNewRowWithEntity method returns the primary key as an NSDictionary, which the code merges with the raw row dictionary before inserting the row into the database. The closeChannel method invocation disconnects the channel from the database.
The insertion can fail for the following reasons:
22 July, 1998. Seejo Pylappan. First Draft.
13 November, 1998. Clif Liu. Second Draft.
16 March, 1999. Clif Liu. Third Draft.