Updating an access database
property will reflect the primary key value of the newly inserted post, even though we never change it explicitly.
If a column is defined with some static default value (e.g.
Note that if you are using My SQL database, you should replace Note: AR is not meant to solve all database-related tasks.
It is best used for modeling database tables in PHP constructs and performing queries that do not involve complex SQLs.
To access a database table, we first need to define an AR class by extending CActive Record.
Each AR class represents a single database table, and an AR instance represents a row in that table.
For example, Postgre SQL treats column names as case-insensitive by default, and we must quote a column in a query condition if the column contains mixed-case letters.
Using lower case would help eliminate this problem. If a table does not have a primary key, it is required that the corresponding AR class specify which column(s) should be the primary key by overriding the To insert a new row into a database table, we create a new instance of the corresponding AR class, set its properties associated with the table columns, and call the save() method to finish the insertion.
One way to change this default value is by explicitly declaring the property in the AR class: Tip: While AR allows us to perform database operations without writing cumbersom SQL statements, we often want to know what SQL statements are executed by AR underneath.
As a result, we can access our data in a more object-oriented way.
For example, we can use the following code to insert a new row to the In the following we describe how to set up AR and use it to perform CRUD operations.
Although Yii DAO can handle virtually any database-related task, chances are that we would spend 90% of our time in writing some SQL statements which perform the common CRUD (create, read, update and delete) operations.
It is also difficult to maintain our code when they are mixed with SQL statements. Active Record (AR) is a popular Object-Relational Mapping (ORM) technique.
The following example shows the minimal code needed for the AR class representing the Tip: Because AR classes are often referenced in many places, we can import the whole directory containing the AR class, instead of including them one by one.