Package rife.database.migrations

Class DbMigration

java.lang.Object

rife.database.migrations.DbMigration

Direct Known Subclasses:

ReversibleDbMigration

public abstract class DbMigration
extends Object

Provides a single declarative database migration.

A migration declares an ordered series of steps in up() by calling one of the add methods. The steps are query builders, literal SQL statements, or DbMigrationAction instances for the data transforms that need Java logic. A migration never executes anything itself, since the steps are merely collected and are afterwards executed by DbMigrations.

The protected factory methods create query builders that are bound to the datasource that is being migrated. Creating such a builder doesn't add a step by itself, since every step has to be added explicitly with one of the add methods.

A migration that extends this class directly is irreversible, which means that rolling it back raises IrreversibleMigrationException. When a migration can be reversed, it extends ReversibleDbMigration instead and also declares the reverse steps in its down method.

Since:

1.10

See Also:

• ReversibleDbMigration
• DbMigrationAction
• DbMigrations

Constructor Summary

Constructors

Constructor	Description
DbMigration()

Method Summary

Modifier and Type	Method	Description
protected DbMigration	add(String sql)	Adds a literal SQL step to this migration.
protected DbMigration	add(DbMigrationAction action)	Adds a Java logic step to this migration.
protected DbMigration	add(Query query)	Adds a query builder step to this migration.
protected AlterTable	alterTable(String table)	Creates a query builder for altering a table.
protected CreateIndex	createIndex(String name)	Creates a query builder for creating an index.
protected CreateSequence	createSequence(String name)	Creates a query builder for creating a sequence.
protected CreateTable	createTable(String table)	Creates a query builder for creating a table.
protected CreateView	createView(String view)	Creates a query builder for creating a view.
protected Datasource	datasource()	Retrieves the datasource that this migration is being collected for.
protected Delete	delete(String table)	Creates a query builder for deleting data.
protected DropIndex	dropIndex(String name)	Creates a query builder for dropping an index.
protected DropSequence	dropSequence(String name)	Creates a query builder for dropping a sequence.
protected DropTable	dropTable(String table)	Creates a query builder for dropping a table.
protected DropView	dropView(String view)	Creates a query builder for dropping a view.
protected Insert	insert(String table)	Creates a query builder for inserting data.
protected Truncate	truncate(String table)	Creates a query builder for truncating a table.
abstract void	up()	Declares the steps that perform this migration.
protected Update	update(String table)	Creates a query builder for updating data.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

DbMigration

public DbMigration()

Method Details

up

public abstract void up()

Declares the steps that perform this migration.

This method will be called while the steps of the migration are being collected; you declare each of them by calling one of the add methods, in the order in which they have to be executed.

Since:

1.10

See Also:

• add(Query)
• add(String)
• add(DbMigrationAction)

add

protected DbMigration add(Query query)

Adds a query builder step to this migration.

This makes it possible to declare the step with the object-oriented query builders so that the SQL that is eventually executed stays database-independent.

Parameters:

query - the query to execute as this step

Returns:

this migration

Since:

1.10

See Also:

• add(String)
• add(DbMigrationAction)

add

protected DbMigration add(String sql)

Adds a literal SQL step to this migration.

This makes it possible to execute statements that the query builders don't cover, at the cost of tying the migration to the SQL dialect that you're writing it in.

Parameters:

sql - the SQL statement to execute as this step

Returns:

this migration

Since:

1.10

See Also:

• add(Query)
• add(DbMigrationAction)

add

protected DbMigration add(DbMigrationAction action)

Adds a Java logic step to this migration.

This makes it possible to perform data transforms that can't be expressed as a single query. The action receives the query manager of the datasource that is being migrated at the moment that the step is executed.

Parameters:

action - the action to execute as this step

Returns:

this migration

Since:

1.10

See Also:

• add(Query)
• add(String)

datasource

protected Datasource datasource()

Retrieves the datasource that this migration is being collected for.

The datasource is only available while the steps are being declared, which is why you can only use it and the query builder factory methods that rely on it from inside up or down.

Returns:

the active datasource

Since:

1.10

createTable

protected CreateTable createTable(String table)

Creates a query builder for creating a table.

The returned builder is bound to the datasource that is being migrated and still has to be added as a step with add(Query).

Parameters:

table - the name of the table to create

Returns:

the CreateTable query builder

Since:

1.10

See Also:

• alterTable(String)
• dropTable(String)

alterTable

protected AlterTable alterTable(String table)

Creates a query builder for altering a table.

The returned builder is bound to the datasource that is being migrated and still has to be added as a step with add(Query). Since each AlterTable query performs exactly one alteration, you add one of them for every alteration that the migration needs.

Parameters:

table - the name of the table to alter

Returns:

the AlterTable query builder

Since:

1.10

See Also:

• createTable(String)
• dropTable(String)

dropTable

protected DropTable dropTable(String table)

Creates a query builder for dropping a table.

The returned builder is bound to the datasource that is being migrated and still has to be added as a step with add(Query).

Parameters:

table - the name of the table to drop

Returns:

the DropTable query builder

Since:

1.10

See Also:

• createTable(String)
• alterTable(String)

createIndex

protected CreateIndex createIndex(String name)

Creates a query builder for creating an index.

The returned builder is bound to the datasource that is being migrated and still has to be added as a step with add(Query).

Parameters:

name - the name of the index to create

Returns:

the CreateIndex query builder

Since:

1.10

See Also:

• dropIndex(String)

dropIndex

protected DropIndex dropIndex(String name)

Creates a query builder for dropping an index.

The returned builder is bound to the datasource that is being migrated and still has to be added as a step with add(Query).

Parameters:

name - the name of the index to drop

Returns:

the DropIndex query builder

Since:

1.10

See Also:

• createIndex(String)

createView

protected CreateView createView(String view)

Creates a query builder for creating a view.

The returned builder is bound to the datasource that is being migrated and still has to be added as a step with add(Query).

Parameters:

view - the name of the view to create

Returns:

the CreateView query builder

Since:

1.10

See Also:

• dropView(String)

dropView

protected DropView dropView(String view)

Creates a query builder for dropping a view.

The returned builder is bound to the datasource that is being migrated and still has to be added as a step with add(Query).

Parameters:

view - the name of the view to drop

Returns:

the DropView query builder

Since:

1.10

See Also:

• createView(String)

createSequence

protected CreateSequence createSequence(String name)

Creates a query builder for creating a sequence.

The returned builder is bound to the datasource that is being migrated and still has to be added as a step with add(Query).

Parameters:

name - the name of the sequence to create

Returns:

the CreateSequence query builder

Since:

1.10

See Also:

• dropSequence(String)

dropSequence

protected DropSequence dropSequence(String name)

Creates a query builder for dropping a sequence.

The returned builder is bound to the datasource that is being migrated and still has to be added as a step with add(Query).

Parameters:

name - the name of the sequence to drop

Returns:

the DropSequence query builder

Since:

1.10

See Also:

• createSequence(String)

truncate

protected Truncate truncate(String table)

Creates a query builder for truncating a table.

The returned builder is bound to the datasource that is being migrated and still has to be added as a step with add(Query).

Parameters:

table - the name of the table to truncate

Returns:

the Truncate query builder

Since:

1.10

See Also:

• dropTable(String)
• delete(String)

insert

protected Insert insert(String table)

Creates a query builder for inserting data.

The returned builder is bound to the datasource that is being migrated and still has to be added as a step with add(Query).

Parameters:

table - the name of the table to insert into

Returns:

the Insert query builder

Since:

1.10

See Also:

• update(String)
• delete(String)

update

protected Update update(String table)

Creates a query builder for updating data.

The returned builder is bound to the datasource that is being migrated and still has to be added as a step with add(Query).

Parameters:

table - the name of the table to update

Returns:

the Update query builder

Since:

1.10

See Also:

• insert(String)
• delete(String)

delete

protected Delete delete(String table)

Creates a query builder for deleting data.

The returned builder is bound to the datasource that is being migrated and still has to be added as a step with add(Query).

Parameters:

table - the name of the table to delete from

Returns:

the Delete query builder

Since:

1.10

See Also:

• insert(String)
• update(String)
• truncate(String)