How do I run a specific migration in yii2?
To run specific migration, you can mark(skip) migrations upto just before one you want run.
How to migrate database in yii2?
Creating a Migration
- Step 1 − Inside the project root of the basic application template open the console window and run.
- Step 2 − To add a new table to the database, modify the migration file this way.
- Step 3 − To upgrade a database, run this command.
- Step 4 − To apply only three available migrations, you may run.
How do I run a query in yii?
Call yii\db\QueryBuilder to generate a SQL statement based on the current construct of yii\db\Query; Create a yii\db\Command object with the generated SQL statement; Call a query method (e.g. queryAll()) of yii\db\Command to execute the SQL statement and retrieve the data.
How to create command in yii2?
A command object is usually created by calling yii\db\Connection::createCommand(). The SQL statement it represents can be set via the $sql property. To execute a non-query SQL (such as INSERT, DELETE, UPDATE), call execute().
What is migration in Yii2?
Migration is the base class for representing a database migration. Migration is designed to be used together with the “yii migrate” command. Migration provides a set of convenient methods for manipulating database data and schema.
How do I convert Yii1 to Yii2?
As you know, there’s no way to upgrade from Yii1 to Yii2 without re-writing code, since the Yii framework has been completely rewritten from the ground up for Yii 2.0. So you can’t just upgrade your application directly on the new version.
What is SQL query builder?
The SQL Query Builder (SQB) is a component of the Data Tools Platform (DTP) SQL Development Tools project. ▪ The SQB is a software tool that allows end-users to create SQL queries using point-click-select and drag-drop gestures.
What is query Builder?
Using Query Builder, you can search and filter database objects, select objects and columns, create relationships between objects, view formatted query results, and save queries with little or no SQL knowledge.
How do you execute a SQL query only if another SQL query has results?
The common table expression ( WITH clause) wraps the first query that we want to execute no matter what. We then select from the first query, and use UNION ALL to combine the result with the result of the second query, which we’re executing only if the first query didn’t yield any results (through NOT EXISTS ).
How can I connect database in Yii?
Creating DB Connections To access a database, you first need to connect to it by creating an instance of yii\db\Connection: $db = new yii\db\Connection([ ‘dsn’ => ‘mysql:host=localhost;dbname=example’, ‘username’ => ‘root’, ‘password’ => ”, ‘charset’ => ‘utf8’, ]);
What is difference between Yii1 and Yii2?
The old Yii1 code can be deprecated and replaced as the new Yii2 code is written. There are many differences between versions 1.1 and 2.0 of Yii as the framework was completely rewritten for 2.0. As a result, upgrading from version 1.1 is not as trivial as upgrading between minor versions.
Why do we need database migration in yii2?
Database Migration is a very useful feature in Yii2 to maintain and monitor your database structure. It’s a version-controlled for your database structure so that we can keep track of our database structure changes. To view the complete list of yii migration commands, run the following command:
How to add a column to the Yii database?
Sometimes you need to add or drop a column from a specific table. You can use addColumn () and dropColumn () methods. Step 1 − Create a new migration. Step 2 − Modify the newly created migration file this way. Now, if you run ./yii migrate, the category column should be added to the news table.
When to drop category column in Yii migration?
On the contrary, if you run ./yii migrate/down 1, the category column should be dropped. When performing DB migrations, it is important to ensure each migration has succeded or failed. It is recommended to enclose DB operations in a transaction.
How to create a database migration in PHP?
Let us create a new database migration. Step 1 − Inside the project root of the basic application template open the console window and run. The above command will create a new migration file (m160113_102634_add_news_table.php in this case) in the migrations folder. Each DB migrations is a PHP class extending the yii\\db\\Migration class.