Class: AlRdbwPostgres

Inherits:
AlRdbw
  • Object
show all
Defined in:
lib/al_rdbw_postgres.rb,
lib/al_persist_postgres.rb

Overview

リレーショナルデータベースラッパー PostgreSQL版

Instance Attribute Summary collapse

Attributes inherited from AlRdbw

#fields, #flag_transaction, #handle, #select_data_type, #select_fetch_mode

Instance Method Summary collapse

Methods inherited from AlRdbw

#close, connect, #get_handle, inherited, #initialize, #transaction_active?

Constructor Details

This class inherits a constructor from AlRdbw

Instance Attribute Details

#result ⇒ Object (readonly)

Returns クエリ実行結果.

Returns:

  • (Object) —

    クエリ実行結果



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

def result
  @result
end

Instance Method Details

#[](tname) ⇒ AlPersistSqlite

tableを指定して、Persistオブジェクトを生成 syntax sugar

Parameters:

  • tname (String) —

    テーブル名

Returns:



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# File 'lib/al_persist_postgres.rb', line 53

def []( tname )
  return AlPersistPostgres.new( self, tname )
end

#commit ⇒ Boolean

TODO:

トランザクションコミット

実装中。トランザクションがSQLレベルで失敗する条件をテストして返り値に反映する

Returns:

  • (Boolean) —

    成否



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# File 'lib/al_rdbw_postgres.rb', line 250

def commit()
  return false  if ! @flag_transaction
  @result = get_handle().exec( "commit transaction;" )
  @result.clear()
  @flag_transaction = false
  return true
end

#delete(table, where_cond) ⇒ Hash

delete文の発行ヘルパー

Parameters:

  • table (String) —

    テーブル名

  • where_cond (Hash) —

    where条件

Returns:

  • (Hash) —

    結果のHash



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# File 'lib/al_rdbw_postgres.rb', line 219

def delete( table, where_cond )
  (where, wval) = make_where_condition( where_cond )
  sql = "delete from #{table} where #{where};"
  @result = get_handle().exec( sql, wval )
  ret = { :cmdtuples=>@result.cmdtuples }

  @result.clear()
  return ret
end

#execute(sql, var = nil) ⇒ Hash Also known as: exec

Note:

任意SQLの実行

アクションクエリの実行用。selectは、select()メソッドを使う。

Parameters:

  • sql (String) —

    SQL文

  • var (Array) (defaults to: nil) —

    パラメータクエリ用変数

Returns:

  • (Hash) —

    結果



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# File 'lib/al_rdbw_postgres.rb', line 46

def execute( sql, var = nil )
  @result = get_handle().exec( sql, var )
  ret = { :cmdtuples=>@result.cmdtuples }
  @result.clear()
  return ret
end

#insert(table, values) ⇒ Hash

insert文の発行ヘルパー

Parameters:

  • table (String) —

    テーブル名

  • values (Hash) —

    insertする値のhash

Returns:

  • (Hash) —

    結果のHash



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# File 'lib/al_rdbw_postgres.rb', line 151

def insert( table, values )
  col = ""
  plh = ""
  val = []
  cnt = 1
  values.each do |k,v|
    col << "#{k},"
    plh << "$#{cnt},"
    cnt += 1
    if v.class == Array
      val << v.join( ',' )
    else
      val << v
    end
  end
  col.chop!
  plh.chop!

  sql = "insert into #{table} (#{col}) values (#{plh});"
  @result = get_handle().exec( sql, val )
  ret = { :cmdtuples=>@result.cmdtuples }

  @result.clear()
  return ret
end

#open_connection ⇒ Object

RDBサーバとのコネクションを開始する



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# File 'lib/al_rdbw_postgres.rb', line 27

def open_connection()
  return false  if ! @dsn

  @handle = PG::Connection.new( @dsn )
  @handle.set_client_encoding( AL_CHARSET.to_s )
  @handle.type_map_for_results = PG::BasicTypeMapForResults.new(@handle)
  @dsn = nil
end

#rollback ⇒ Boolean

トランザクションロールバック

Returns:

  • (Boolean) —

    成否



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# File 'lib/al_rdbw_postgres.rb', line 264

def rollback()
  return false  if ! @flag_transaction
  @result = get_handle().exec( "rollback transaction;" )
  @result.clear()
  @flag_transaction = false
  return true
end

#select(sql, where_cond = nil) ⇒ Array<Hash>

select文の発行ヘルパー

Examples:

where condition
 use Array
  select( "select * from t1 where id=$1;", [2] )
 use Hash
  select( "select * from t1 _WHERE_;",
    { :id=>2, :age=>nil, "name like"=>"a%" } )

Parameters:

  • sql (String) —

    SQL文

  • where_cond (Array, Hash, String) (defaults to: nil) —

    where条件

Returns:

  • (Array<Hash>) —

    結果の配列



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# File 'lib/al_rdbw_postgres.rb', line 69

def select( sql, where_cond = nil )
  conn = get_handle()

  case where_cond
  when NilClass
    conn.send_query( sql )

  when Array
    conn.send_query_params( sql, where_cond );

  when Hash
    s = sql.split( '_WHERE_' )
    raise "SQL error in select()"  if s.size != 2
    (where, val) = make_where_condition( where_cond )
    conn.send_query_params( "#{s[0]} where #{where} #{s[1]}", val )

  when String
    conn.send_query( sql.sub( '_WHERE_', "where #{where_cond}" ))

  else
    raise "where_cond error in AlRdbwPostgres#select()"
  end

  conn.set_single_row_mode  if @select_fetch_mode == :ROW

  # get field name
  @result = conn.get_result() or return @select_fetch_mode == :ROW ? nil : []
  @result.check_result
  @fields = @result.fields().map {|field| field.to_sym }

  # get data
  ret = []
  case @select_data_type
  when :ARRAY         # Array<Array>で返す
    @result.each_row {|row| ret << row }

  else                # Array<Hash>で返す（標準）
    @result.each_row {|row| ret << [@fields, row].transpose.to_h }
  end

  return ret[0]  if @select_fetch_mode == :ROW

  @result.clear()
  conn.get_result()   # libqp needs this operation.
  return ret
end

#select_next ⇒ Array, ...

シングル行モード(select_fetch_mode = :ROW)の場合の次行取得

res = @db.select( sql ) p @db.fields while res

p res
res = db.select_next()

end

Returns:

  • (Array, Hash, Nil) —

    結果



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# File 'lib/al_rdbw_postgres.rb', line 129

def select_next()
  @result = get_handle().get_result() or return nil
  @result.check_result

  case @select_data_type
  when :ARRAY
    @result.each_row {|row| return row }

  else
    @result.each_row {|row| return [@fields, row].transpose.to_h }
  end
end

#table(tname, pkey = nil) ⇒ AlPersistSqlite

tableを指定して、Persistオブジェクトを生成

Parameters:

  • tname (String) —

    テーブル名

  • pkey (Array<String,Symbol>, String, Symbol) (defaults to: nil) —

    プライマリキー

Returns:



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# File 'lib/al_persist_postgres.rb', line 43

def table( tname, pkey = nil )
  return AlPersistPostgres.new( self, tname, pkey )
end

#transaction ⇒ Boolean

トランザクション開始

Returns:

  • (Boolean) —

    成否



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# File 'lib/al_rdbw_postgres.rb', line 235

def transaction()
  return false  if @flag_transaction
  @result = get_handle().exec( "begin transaction;" )
  @result.clear()
  return @flag_transaction = true
end

#update(table, values, where_cond) ⇒ Hash

update文の発行ヘルパー

Parameters:

  • table (String) —

    テーブル名

  • values (Hash) —

    updateする値のhash

  • where_cond (Hash) —

    where条件

Returns:

  • (Hash) —

    結果のHash



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# File 'lib/al_rdbw_postgres.rb', line 186

def update( table, values, where_cond )
  columns = ""
  cnt = 1
  val = []
  values.each do |k,v|
    columns << "#{k}=$#{cnt},"
    cnt += 1
    if v.class == Array
      val << v.join( ',' )
    else
      val << v
    end
  end
  columns.chop!

  (where, wval) = make_where_condition( where_cond, cnt )

  sql = "update #{table} set #{columns} where #{where};"
  @result = get_handle().exec( sql, val + wval )
  ret = { :cmdtuples=>@result.cmdtuples }

  @result.clear()
  return ret
end