Module: M4DBI

Defined in:
lib/m4dbi.rb,
lib/m4dbi/error.rb,
lib/m4dbi/model.rb,
lib/m4dbi/version.rb,
lib/m4dbi/database.rb,
lib/m4dbi/statement.rb,
lib/m4dbi/collection.rb

Defined Under Namespace

Classes: Collection, Database, Error, Model, Statement

Constant Summary collapse

VERSION = 
'0.9.0'

Class Method Summary collapse

Class Method Details

.connect(*args) ⇒ Object 



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# File 'lib/m4dbi.rb', line 21

def self.connect( *args )
  dbh = M4DBI::Database.new( RDBI.connect( *args ) )
  trait :last_dbh => dbh
  dbh
end

.Model(table, options = Hash.new) ⇒ Object

Define a new M4DBI::Model like this:

class Post < M4DBI::Model( :posts ); end

You can specify the primary key column(s) using an option, like so:

class Author < M4DBI::Model( :authors, pk: [ 'auth_num' ] ); end



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# File 'lib/m4dbi/model.rb', line 504

def self.Model( table, options = Hash.new )
  h = options[ :dbh ] || M4DBI.last_dbh
  if h.nil? || ! h.connected?
    raise M4DBI::Error.new( "Attempted to create a Model class without first connecting to a database." )
  end
  pk_ = options[ :pk ] || [ 'id' ]
  if not pk_.respond_to? :each
    raise M4DBI::Error.new( "Primary key must be enumerable (was given #{pk_.inspect})" )
  end

  model_key =
    if h.respond_to? :database_name
      "#{h.database_name}::#{table}"
    else
      table
    end

  @models ||= Hash.new
  @models[ model_key ] ||= Class.new( M4DBI::Model ) do |klass|
    klass.trait( {
      :dbh       => h,
      :table     => table,
      :pk        => pk_,
      :columns   => h.table_schema( table.to_sym ).columns,
      :hooks => {
        after_create: [],
        after_update: [],
        before_delete: [],
        after_delete: [],
        active: true,
      },
    } )

    meta_def( 'pk_str'.to_sym ) do
      if pk.size == 1
        pk[ 0 ].to_s
      else
        pk.to_s
      end
    end

    if defined?( RDBI::Driver::PostgreSQL ) && RDBI::Driver::PostgreSQL === h.driver
      # TODO: This is broken for non-SERIAL or multi-column primary keys
      meta_def( "last_record".to_sym ) do |dbh_|
        self.s1 "SELECT * FROM #{table} WHERE #{pk_str} = currval( '#{table}_#{pk_str}_seq' );"
      end
    elsif defined?( RDBI::Driver::MySQL ) && RDBI::Driver::MySQL === h.driver
      meta_def( "last_record".to_sym ) do |dbh_|
        self.s1 "SELECT * FROM #{table} WHERE #{pk_str} = LAST_INSERT_ID();"
      end
    elsif defined?( RDBI::Driver::SQLite3 ) && RDBI::Driver::SQLite3 === h.driver
      meta_def( "last_record".to_sym ) do |dbh_|
        self.s1 "SELECT * FROM #{table} WHERE #{pk_str} = last_insert_rowid();"
      end
    # TODO: more DB drivers
    end

    klass.trait[ :columns ].each do |col|

      colname = col[ 'name' ]
      method = colname.to_sym
      while klass.method_defined? method
        method = "#{method}_".to_sym
      end

      # Column readers
      class_def( method ) do
        @row[ colname ]
      end

      # Column writers

      class_def( "#{method}=".to_sym ) do |new_value|
        state_before = self.to_h
        stm = prepare("UPDATE #{table} SET #{colname} = ? WHERE #{pk_clause}")
        num_changed = stm.execute(
          new_value,
          *pk_values
        ).affected_count
        if defined?( RDBI::Driver::PostgreSQL ) && RDBI::Driver::PostgreSQL === h.driver
          stm.finish
        end
        if num_changed > 0
          @row[ colname ] = new_value
        end
        if self.class.hooks[:active]
          self.class.hooks[:after_update].each do |block|
            self.class.hooks[:active] = false
            block.yield state_before, self
            self.class.hooks[:active] = true
          end
        end
        new_value
      end

      class_def( '[]='.to_sym ) do |colname, new_value|
        stm = prepare("UPDATE #{table} SET #{colname} = ? WHERE #{pk_clause}")
        num_changed = stm.execute(
          new_value,
          *pk_values
        ).affected_count
        if num_changed > 0
          @row[ colname ] = new_value
        end
      end

    end
  end
end