Module: RR::ConnectionExtenders::MysqlExtender

Defined in:
lib/rubyrep/connection_extenders/mysql_extender.rb

Overview

Provides various MySQL specific functionality required by Rubyrep.

Instance Method Summary collapse

Instance Method Details

#column_aware_quote(value, column) ⇒ String

Quotes the value so it can be used in SQL insert / update statements.

Parameters:

  • value (Object) —

    the target value

  • column (ActiveRecord::ConnectionAdapters::MySQL::Column) —

    the target column

Returns:

  • (String) —

    the quoted string



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# File 'lib/rubyrep/connection_extenders/mysql_extender.rb', line 63

def column_aware_quote(value, column)
  if column.sql_type == 'blob' and RUBY_PLATFORM == 'java'
    quote(column.type_cast_for_database(value))
  else
    quote(value)
  end
end

#fixed_type_cast(value, column) ⇒ Object

Casts a value returned from the database back into the according ruby type.

Parameters:

  • value (Object) —

    the received value

  • column (ActiveRecord::ConnectionAdapters::AbstractMysqlAdapter::Column) —

    the originating column

Returns:

  • (Object) —

    the casted value



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# File 'lib/rubyrep/connection_extenders/mysql_extender.rb', line 76

def fixed_type_cast(value, column)
  column.type_cast_from_database value
end

#primary_key_names(table) ⇒ Object

Returns an ordered list of primary key column names of the given table



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# File 'lib/rubyrep/connection_extenders/mysql_extender.rb', line 10

def primary_key_names(table)
  row = self.select_one(<<-end_sql)
    select table_name from information_schema.tables 
    where table_schema = database() and table_name = '#{table}'
  end_sql
  if row.nil?
    raise "table '#{table}' does not exist"
  end
  
  rows = self.select_all(<<-end_sql)
    select column_name from information_schema.key_column_usage
    where table_schema = database() and table_name = '#{table}' 
    and constraint_name = 'PRIMARY'
    order by ordinal_position
  end_sql

  columns = rows.map {|_row| _row['column_name']}
  columns
end

#referenced_tables(tables) ⇒ Object

Returns for each given table, which other tables it references via foreign key constraints.

  • tables: an array of table names

Returns: a hash with

  • key: name of the referencing table

  • value: an array of names of referenced tables



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# File 'lib/rubyrep/connection_extenders/mysql_extender.rb', line 36

def referenced_tables(tables)
  rows = self.select_all(<<-end_sql)
    select distinct table_name as referencing_table, referenced_table_name as referenced_table
    from information_schema.key_column_usage
    where table_schema = database()
    and table_name in ('#{tables.join("', '")}')
  end_sql
  result = {}
  rows.each do |row|
    unless result.include? row['referencing_table']
      result[row['referencing_table']] = []
    end
    if row['referenced_table'] != nil
      result[row['referencing_table']] << row['referenced_table']
    end
  end
  tables.each do |table|
    result[table] = [] unless result.include? table
  end
  result
end