Class: Scenic::Adapters::Mysql

Inherits:
Object
  • Object
show all
Defined in:
lib/scenic/adapters/mysql.rb,
lib/scenic/adapters/mysql/views.rb,
lib/scenic/adapters/mysql/errors.rb,
lib/scenic/adapters/mysql/indexes.rb,
lib/scenic/adapters/mysql/connection.rb

Overview

An adapter for managing Mysql views.

These methods are used internally by Scenic and are not intended for direct use. Methods that alter database schema are intended to be called via Statements, while #refresh_materialized_view is called via Scenic.database.

The methods are documented here for insight into specifics of how Scenic integrates with Mysql and the responsibilities of Scenic::Adapters.

Defined Under Namespace

Classes: ConcurrentRefreshesNotSupportedError, Connection, Indexes, MaterializedViewsNotSupportedError, Views

Instance Method Summary collapse

Constructor Details

#initialize(connectable = ActiveRecord::Base) ⇒ Mysql

Creates an instance of the Scenic Mysql adapter.

Postgres is the default adapter for Scenic. To use this Mysql adapter, follow the example bellow

Examples:

Scenic.configure do |config|
  config.adapter = Scenic::Adapters::Mysql.new
end

Parameters:

  • connectable (#connection) (defaults to: ActiveRecord::Base) —

    An object that returns the connection for Scenic to use. Defaults to ‘ActiveRecord::Base`.



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# File 'lib/scenic/adapters/mysql.rb', line 35

def initialize(connectable = ActiveRecord::Base)
  @connectable = connectable
end

Instance Method Details

#create_materialized_view(_name, _sql_definition) ⇒ void

This method returns an undefined value.

materialized views.

Raises:



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# File 'lib/scenic/adapters/mysql.rb', line 122

def create_materialized_view(_name, _sql_definition)
  raise MaterializedViewsNotSupportedError
end

#create_view(name, sql_definition) ⇒ void

This method returns an undefined value.

Creates a view in the database.

This is typically called in a migration via Statements#create_view.

Parameters:

  • name —

    The name of the view to create

  • sql_definition —

    The SQL schema for the view.



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# File 'lib/scenic/adapters/mysql.rb', line 57

def create_view(name, sql_definition)
  execute "CREATE VIEW #{quote_table_name(name)} AS #{sql_definition};"
end

#drop_materialized_view(_name) ⇒ void

This method returns an undefined value.

materialized views.

Raises:



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# File 'lib/scenic/adapters/mysql.rb', line 139

def drop_materialized_view(_name)
  raise MaterializedViewsNotSupportedError
end

#drop_view(name) ⇒ void

This method returns an undefined value.

Drops the named view from the database

This is typically called in a migration via Statements#drop_view.

Parameters:

  • name —

    The name of the view to drop



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# File 'lib/scenic/adapters/mysql.rb', line 114

def drop_view(name)
  execute "DROP VIEW #{quote_table_name(name)};"
end

#refresh_materialized_view(_name, _concurrently: false) ⇒ void

This method returns an undefined value.

materialized views.

Raises:



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# File 'lib/scenic/adapters/mysql.rb', line 148

def refresh_materialized_view(_name, _concurrently: false)
  raise MaterializedViewsNotSupportedError
end

#replace_view(name, sql_definition) ⇒ void

This method returns an undefined value.

Replaces a view in the database using ‘CREATE OR REPLACE VIEW`.

This results in a ‘CREATE OR REPLACE VIEW`. Most of the time the explicitness of the two step process used in #update_view is preferred to `CREATE OR REPLACE VIEW` because the former ensures that the view you are trying to update did, in fact, already exist. Additionally, `CREATE OR REPLACE VIEW` is allowed only to add new columns to the end of an existing view schema. Existing columns cannot be re-ordered, removed, or have their types changed. Drop and create overcomes this limitation as well.

However, when there is a tangled dependency tree ‘CREATE OR REPLACE VIEW` can be preferable.

This is typically called in a migration via Statements#replace_view.

Parameters:

  • name —

    The name of the view to update

  • sql_definition —

    The SQL schema for the updated view.



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# File 'lib/scenic/adapters/mysql.rb', line 103

def replace_view(name, sql_definition)
  execute "CREATE OR REPLACE VIEW #{quote_table_name(name)} AS #{sql_definition};"
end

#update_materialized_view(_name, _sql_definition) ⇒ void

This method returns an undefined value.

materialized views.

Raises:



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# File 'lib/scenic/adapters/mysql.rb', line 130

def update_materialized_view(_name, _sql_definition)
  raise MaterializedViewsNotSupportedError
end

#update_view(name, sql_definition) ⇒ void

This method returns an undefined value.

Updates a view in the database.

This results in a #drop_view followed by a #create_view. The explicitness of that two step process is preferred to ‘CREATE OR REPLACE VIEW` because the former ensures that the view you are trying to update did, in fact, already exist. Additionally, `CREATE OR REPLACE VIEW` is allowed only to add new columns to the end of an existing view schema. Existing columns cannot be re-ordered, removed, or have their types changed. Drop and create overcomes this limitation as well.

This is typically called in a migration via Statements#update_view.

Parameters:

  • name —

    The name of the view to update

  • sql_definition —

    The SQL schema for the updated view.



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# File 'lib/scenic/adapters/mysql.rb', line 77

def update_view(name, sql_definition)
  drop_view(name)
  create_view(name, sql_definition)
end

#views ⇒ Array<Scenic::View>

Returns an array of views in the database.

This collection of views is used by the [Scenic::SchemaDumper] to populate the ‘schema.rb` file.

Returns:

  • (Array<Scenic::View>) 


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# File 'lib/scenic/adapters/mysql.rb', line 45

def views
  Views.new(connection).all
end