Module: Foreigner::ConnectionAdapters::MysqlAdapter

Includes:
Semantics::Sql2003
Defined in:
lib/foreigner/connection_adapters/mysql_adapter.rb

Instance Method Summary collapse

Methods included from Semantics::Sql2003

#add_foreign_key, #foreign_key_definition, #remove_foreign_key, #supports_foreign_keys?

Instance Method Details

#foreign_keys(table_name) ⇒ Object 



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# File 'lib/foreigner/connection_adapters/mysql_adapter.rb', line 12

def foreign_keys(table_name)
  fk_info = select_all %{
    SELECT fk.referenced_table_name as 'to_table'
          ,fk.referenced_column_name as 'primary_key'
          ,fk.column_name as 'column'
          ,fk.constraint_name as 'name'
    FROM information_schema.key_column_usage fk
    WHERE fk.referenced_column_name is not null
      AND fk.table_schema = '#{@config[:database]}'
      AND fk.table_name = '#{table_name}'
  }

  create_table_info = select_one("SHOW CREATE TABLE #{quote_table_name(table_name)}")["Create Table"]

  fk_info.map do |row|
    options = {:column => row['column'], :name => row['name'], :primary_key => row['primary_key']}

    if create_table_info =~ /CONSTRAINT #{quote_column_name(row['name'])} FOREIGN KEY .* REFERENCES .* ON DELETE (CASCADE|SET NULL)/
      options[:dependent] = case $1
        when 'CASCADE'  then :delete
        when 'SET NULL' then :nullify
        end
    end
    ForeignKeyDefinition.new(table_name.to_s, row['to_table'], options)
  end
end

#sql_for_remove_foreign_key(table, foreign_key_name) ⇒ Object

Override SQL2003 Semantics for MySQL



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# File 'lib/foreigner/connection_adapters/mysql_adapter.rb', line 8

def sql_for_remove_foreign_key(table, foreign_key_name)
  "ALTER TABLE #{quote_table_name(table)} DROP FOREIGN KEY #{quote_column_name(foreign_key_name)}"
end