Database Migration

Migration is database version control, which helps developers complete table structure changes and data migration in daily work.

Quick start

Generate migration

First, you need to install Sutando's command line tool and generate a configuration file.

bash

$ npm install -g sutando
$ sutando init

This will generate a sutando.config.js file in the project directory, which is used to set database connection and other information.

// Update with your config settings.

module.exports = {
   client: 'mysql2',
   connection: {
     host: 'localhost',
     database: 'database',
     user: 'root',
     password: 'password'
   },
   migrations: {
     table: 'migrations',
     path: 'migrations'
   },
   models: {
     path: 'models',
   }
};

You can then use the migrate:make command to generate database migrations. New migration files are placed in your migrations directory by default. Each migration file name contains a timestamp to allow Sutando to determine the order of migrations:

bash

$ sutando migrate:make create_flights_table

Sutando will use the name of the migration file to guess the table name and whether the migration will create a new table. If Sutando is able to determine the name of the table from the name of the migration file, it will prepopulate the specified table in the generated migration file, or you can manually specify the table name directly in the migration file.

If you want to specify a custom path for the generated migrations, you can use the --path option when executing the migrate:make command. The given path should be relative to the path where the command is executed.

Migration structure

The migration class contains two methods: up and down. The up method is used to add a new table, column or index to the database, while the down method is used to undo the operation performed by the up method. .

In both methods, you can use Schema builders to expressively create and modify tables. To learn about all the methods available on the Schema builder, check out its documentation. For example, the following migration creates a flights table:

const { Migration } = require('sutando');

module.exports = class extends Migration {
  /**
   * Run the migrations.
   */
  async up(schema) {
    await schema.createTable('flights', (table) => {
      table.increments('id');
      table.string('name');
      table.string('airline');
      table.timestamps();
    });
  }

  /**
   * Reverse the migrations.
   */
  async down(schema) {
    await schema.dropTableIfExists('flights');
  }
};

Execute migration

Execute the migrate:run command to run all unexecuted migrations:

bash

$ sutando migrate:run

If you want to see which migrations have been performed so far, you can use the migrate:status command:

bash

$ sutando migrate:status

Rollback migration

If you want to roll back the last migration operation, you can use migrate:rollback. This command will roll back the last "batch" of migrations, which may include multiple migration files:

bash

$ sutando migrate:rollback

You can roll back a specified number of migrations by adding the step parameter to the rollback command. For example, the following command will roll back the last five migrations:

bash

$ sutando migrate:rollback --step=5

Tables

Create tables

Next we will create a new data table using the createTable method. createTable accepts two parameters: the first parameter is the table name, and the second parameter is a callback function:

const { Migration } = require('sutando');

module.exports = class extends Migration {
   /**
     * Run the migrations.
     */
   async up(schema) {
     await schema.createTable('users', (table) => {
       table.increments('id');
       table.string('name');
       table.string('email');
       table.timestamps();
     });
   }

   /**
     * Reverse the migrations.
     */
   async down(schema) {
     await schema.dropTableIfExists('users');
   }
};

When you create a table, you can use the Database Structure Builder's columns method to define the table's columns.

Check if table/column exists

You can check whether a table or column exists using the hasTable and hasColumn methods:

if (await schema.hasTable('users')) {
   // "users" table exists...
}

if (await schema.hasColumn('users', 'email')) {
   // The "users" table exists and has the "email" column...
}

Additionally, a number of other properties and methods are available to define other places where the table is created. When using MySQL, you can use the engine method to specify the storage engine of the table:

await schema.createTable('users', (table) => {
   table.engine('InnoDB');

   // ...
});

The charset and collate methods can be used to specify the character set and collation for tables created when using MySQL:

await schema.createTable('users', (table) => {
   table.charset('utf8mb4');
   table.collate('utf8mb4_unicode_ci');

   // ...
});

If you want to add a "comment" to a database table, you can call the comment method on the table instance. Currently only MySQL and Postgres support table comments:

await schema.createTable('calculations', (table) => {
   table.comment('Business calculations');

   // ...
});

Update tables

Schema's table method can be used to update an existing table. Like the createTable method, the table method accepts two parameters: the name of the table and a callback function that can be used to add columns or indexes to the table:

await schema.createTable('users', (table) => {
   table.integer('votes');
});

Rename/delete tables

To rename an existing table, use the renameTable method:

await schema.renameTable(from, to);

To drop an existing table, you can use the dropTable or dropTableIfExists method:

await schema.dropTable('users');

await schema.dropTableIfExists('users');

Columns

Create Columns

Schema's table method can be used to update a table. Like the createTable method, the table method accepts two parameters: the table name and a callback function that can be used to add columns to the table:

await schema.table('users', (table) => {
   table.integer('votes');
});

Available column types

Schema builders provide a variety of methods for creating columns of corresponding types in tables. All available methods are listed below:

bigIncrements

The bigIncrements method is used to create an auto-incrementing UNSIGNED BIGINT type (primary key) column in the data table:

table.bigIncrements('id');

bigInteger

The bigInteger method is used to create a BIGINT type column in the data table:

table.bigInteger('votes');

binary

The binary method is used to create a BLOB type column in the data table:

table.binary('photo');

boolean

The boolean method is used to create a BOOLEAN type column in the data table:

table.boolean('confirmed');

datetime

The datetime method is used to create a DATETIME type column in the data table. The optional parameter is the total number of digits of precision:

table.datetime('created_at', { precision: 6 });

date

The date method is used to create a DATE type column in the data table:

table.date('date');

decimal

The decimal method is used to create a DECIMAL type column in the data table. The optional parameters are the total number of valid words and the total number of decimal places:

table.decimal('amount');
table.decimal('amount', 8, 2);

double

The double method is used to create a DOUBLE type column in the data table. The optional parameters are the total number of valid words and the total number of decimal places:

table.double('amount', 8, 2);

enum

The enum method is used to create a column of type ENUM in the data table:

table.enum('difficulty', ['easy', 'hard']);

float

The float method is used to create a FLOAT type column in the data table. The optional parameters are the total number of valid words and the total number of decimal places:

table.float('amount', 8, 2);

geometry

The geometry method is equivalent to GEOMETRY:

table.geometry('positions');

increments

The increments method creates an auto-incrementing column equivalent to UNSIGNED INTEGER as the primary key:

table.increments('id');

integer

The integer method is used to create a column of type INTEGER in the data table:

table.integer('votes');

json

The json method is used to create a JSON type column in the data table:

table.json('options');

jsonb

The jsonb method is used to create a JSONB type column in the data table:

table.jsonb('options');

point

The point method is used to create a POINT type column in the data table:

table.point('position');

smallint

The smallint method is used to create a SMALLINT type column in the data table:

table.smallint('votes');

string

The string method creates a VARCHAR equivalent column of a given length, equivalent to a VARCHAR of the specified length:

table.string('name', 100);

text

The text method is used to create a TEXT type column in the data table:

table.text('description');

time

The time method creates a TIME equivalent column with optional precision (total number of digits):

table.time('sunrise', { precision: 6 });

timestamp

The timestamp method creates a column of type TIMESTAMP with an optional precision (total number of digits):

table.timestamp('sunrise', { precision: 6 });

timestamps

The timestamps method creates created_at and updated_at TIMESTAMP equivalent columns:

table.timestamps();

tinyint

The tinyint method is used to create a TINYINT type column in the data table:

table.tinyint('votes');

uuid

The uuid method is used to create a UUID type column in the data table:

table.uuid('id');

Columns modifiers

In addition to the column types listed above, there are several "modifiers" that can be used when adding columns to a database table. For example, if you want to set a column to be "nullable", you can use the nullable method:

await schema.table('users', (table) => {
   table.string('email').nullable();
})

The following table shows all available column modifiers. This list does not include index modifiers:

Modifier	Description
`.after('column')`	Place the column "after" other columns (MySQL)
`.charset('utf8mb4')`	Specify the character set for this column (MySQL)
`.collate('utf8_unicode_ci')`	Specify the collation for this column (MySQL/PostgreSQL/SQL Server)
`.comment('my comment')`	Add a comment to the column (MySQL/PostgreSQL)
`.defaultTo(value)`	Specify a "default value" for the column
`.first()`	Place the column "first" in the table (MySQL)
`.nullable()`	Allows NULL values to be inserted into this column
`.unsigned()`	Set a column of type INTEGER to UNSIGNED (MySQL)

Modify columns

The alter method can modify an existing column type to a new type or modify attributes. For example, you might want to increase the length of the string column by using the alter method to increase the length of the name column from 25 to 50. So, we can simply update the column properties and call the alter method:

await schema.table('users', (table) => {
   table.string('name', 50).alter();
});

When modifying a column, you must explicitly include all modifiers that you want to retain on the column definition - any missing attributes will be discarded. For example, in order to preserve the unsigned, default, and comment attributes, you must explicitly modify each attribute when modifying the column.

await schema.table('users', (table) => {
   table.integer('votes').unsigned().defaultTo(1).comment('my comment').alter();
});

Rename columns

To rename a column, you can use the renameColumn method provided by the schema builder:

await schema.table('users', (table) => {
   table.renameColumn('from', 'to');
});

Delete columns

To drop a column, you can use the dropColumn method.

await schema.table('users', (table) => {
   table.dropColumn('votes');
});

If you want to delete multiple columns, you can use the dropColumns method.

await schema.table('users', (table) => {
   table.dropColumns('votes', 'avatar', 'location');
});

Indexes

Create indexes

The structure builder supports several types of indexes. The following example creates a new email column with a unique value. We can chain the unique method to the column definition to create an index:

await schema.table('users', (table) => {
   table.string('email').unique();
});

Alternatively, you can create the index after defining the columns. To do this, you should call the unique method on the structure builder, which should be passed the column name of the unique index:

table.unique('email');

You can even pass an array to the index method to create a compound (or synthetic) index:

table.index(['account_id', 'created_at']);

When creating an index, Sutando will automatically generate a reasonable index name, but you can also pass parameters to customize the index name:

table.index(['name', 'last_name'], 'idx_name_last_name');
table.unique('email', {
   indexName: 'unique_email'
});

Available index types

Below are all available indexing methods:

Command	Description
`table.primary('id');`	Add primary key
`table.primary(['id', 'parent_id']);`	Add composite primary key
`table.unique('email');`	Add unique index
`table.index('state');`	Add a normal index

Delete indexes

To delete an index, pass the column array to the dropIndex method, which will delete the index name generated based on the table name, column and key type. You can also specify the index name as the second parameter:

Command	Description
`table.dropPrimary('users', 'users_id_primary');`	Delete the primary key from the "users" table
`table.dropUnique('users', 'users_email_unique');`	Delete the unique index from the "users" table
`table.dropIndex('geo', 'geo_state_index');`	Drop the base index from the "geo" table

Foreign key constraints

Sutando also supports the creation of foreign key constraints for enforcing referential integrity in the database layer. For example, let's define a user_id column on the posts table that references the id column of the users table:

await schema.createTable('posts', (table) => {
   table.integer('user_id').unsigned().notNullable();
   table.string('title', 30);
   table.string('content');

   table.foreign('user_id').references('id').inTable('users');
});

Database Migration ​

Quick start ​

Generate migration ​

Migration structure ​

Execute migration ​

Rollback migration ​

Tables ​

Create tables ​

Check if table/column exists ​

Update tables ​

Rename/delete tables ​

Columns ​

Create Columns ​

Available column types ​

bigIncrements ​

bigInteger ​

binary ​

boolean ​

datetime ​

date ​

decimal ​

double ​

enum ​

float ​

geometry ​

increments ​

integer ​

json ​

jsonb ​

point ​

smallint ​

string ​

text ​

time ​

timestamp ​

timestamps ​

tinyint ​

uuid ​

Columns modifiers ​

Modify columns ​

Rename columns ​

Delete columns ​

Indexes ​

Create indexes ​

Available index types ​

Delete indexes ​

Foreign key constraints ​

Database Migration

Quick start

Generate migration

Migration structure

Execute migration

Rollback migration

Tables

Create tables

Check if table/column exists

Update tables

Rename/delete tables

Columns

Create Columns

Available column types

bigIncrements

bigInteger

binary

boolean

datetime

date

decimal

double

enum

float

geometry

increments

integer

json

jsonb

point

smallint

string

text

time

timestamp

timestamps

tinyint

uuid

Columns modifiers

Modify columns

Rename columns

Delete columns

Indexes

Create indexes

Available index types

Delete indexes

Foreign key constraints