Class: ActiveRecord::ConnectionAdapters::TeradataAdapter

Inherits:
AbstractAdapter
  • Object
show all
Defined in:
lib/active_record/connection_adapters/teradata_adapter.rb

Defined Under Namespace

Classes: BindSubstitution

Instance Method Summary collapse

Constructor Details

#initialize(logger, logon_string, config) ⇒ TeradataAdapter

Returns a new instance of TeradataAdapter.



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# File 'lib/active_record/connection_adapters/teradata_adapter.rb', line 49

def initialize(logger, logon_string, config)
  @logon_string = logon_string
  @charset = config[:charset]
  @database = config[:database]
  @table_name_prefix = config[:table_name_prefix]
  @config = config
  connect
  super @connection, logger
  @visitor = unprepared_visitor
  configure_connection
end

Instance Method Details

#active? ⇒ Boolean

CONNECTION MANAGEMENT ====================================

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/teradata_adapter.rb', line 77

def active?
  @connection.execute_query('SELECT 1')
  true
rescue
  false
end

#adapter_name ⇒ Object 



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# File 'lib/active_record/connection_adapters/teradata_adapter.rb', line 61

def adapter_name
  'teradata'
end

#begin_db_transaction ⇒ Object 



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# File 'lib/active_record/connection_adapters/teradata_adapter.rb', line 158

def begin_db_transaction
  execute_update "BEGIN TRANSACTION"
end

#build_sql_type(column) ⇒ Object

construct the sql type from the teradata column info



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# File 'lib/active_record/connection_adapters/teradata_adapter.rb', line 195

def build_sql_type(column)
  field_type = get_field_type(column['ColumnType'])
  case field_type
  when "varchar"
    "#{field_type}(#{column['ColumnLength']})"
  when "decimal"
    "#{field_type}(#{column['DecimalTotalDigits']},#{column['DecimalFractionalDigits']})"
  else
    field_type
  end
end

#columns(table_name) ⇒ Object

Returns an array of Column objects for the table specified by table_name.



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# File 'lib/active_record/connection_adapters/teradata_adapter.rb', line 171

def columns(table_name)#:nodoc:
  sql = "SELECT * FROM DBC.COLUMNS WHERE TABLENAME='#{table_name}'"
  sql << " AND DATABASENAME='#{@database}'" if @database
  rs = execute(sql)
  rs.entries.collect do |record|
    new_column(
      record['ColumnName'].strip,
      record['DefaultValue'],
      build_sql_type(record),
      record['Nullable'].strip == "Y"
    )
  end
end

#commit_db_transaction ⇒ Object 



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# File 'lib/active_record/connection_adapters/teradata_adapter.rb', line 162

def commit_db_transaction
  execute_update "END TRANSACTION"
end

#disconnect! ⇒ Object

Disconnects from the database if already connected. Otherwise, this method does nothing.



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# File 'lib/active_record/connection_adapters/teradata_adapter.rb', line 94

def disconnect!
  super
  unless @connection.nil?
    @connection.close
    @connection = nil
  end
end

#exec_query(sql, name = 'SQL', binds = []) ⇒ Object

Executes sql statement in the context of this connection using binds as the bind substitutes. name is logged along with the executed sql statement.



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# File 'lib/active_record/connection_adapters/teradata_adapter.rb', line 129

def exec_query(sql, name = 'SQL', binds = [])
  result = execute(sql, name)
  if result && result.count > 0
    ActiveRecord::Result.new(result.entries[0].keys, result.entries.collect{|r|r.collect{|v|v}})
  else
    ActiveRecord::Result.new([],[])
  end
end

#execute(sql, name = nil) ⇒ Object

Executes the SQL statement in the context of this connection.



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# File 'lib/active_record/connection_adapters/teradata_adapter.rb', line 118

def execute(sql, name = nil)
  if name == :skip_logging
    @connection.query(sql)
  else
    log(sql, name) { @connection.query(sql) }
  end
end

#execute_update(sql, name = nil) ⇒ Object 



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# File 'lib/active_record/connection_adapters/teradata_adapter.rb', line 154

def execute_update(sql, name = nil)
  log(sql, name) { @connection.execute_update(sql) }
end

#get_field_type(type) ⇒ Object 



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# File 'lib/active_record/connection_adapters/teradata_adapter.rb', line 207

def get_field_type(type)
  case type.strip
  when "I", "I1"
    "int"
  when "CV"
    "varchar"
  when "DA"
    "date"
  when "D"
    "decimal"
  when "TS"
    "datetime"
  else
    raise "Column type #{type} not supported"
  end
end

#new_column(field, default, type, null) ⇒ Object

Overridden by the adapters to instantiate their specific Column type.



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# File 'lib/active_record/connection_adapters/teradata_adapter.rb', line 190

def new_column(field, default, type, null) # :nodoc:
  Column.new(field, default, type, null)
end

#primary_key(table_name) ⇒ Object 



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# File 'lib/active_record/connection_adapters/teradata_adapter.rb', line 185

def primary_key(table_name)
  columns(table_name).select{|col| col.primary == true}[0].name rescue 'id'
end

#reconnect! ⇒ Object Also known as: reset! 



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# File 'lib/active_record/connection_adapters/teradata_adapter.rb', line 84

def reconnect!
  super
  disconnect!
  connect
  configure_connection
end

#rollback_db_transaction ⇒ Object 



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# File 'lib/active_record/connection_adapters/teradata_adapter.rb', line 166

def rollback_db_transaction
  execute_update "ROLLBACK"
end

#select(sql, name = nil, binds = []) ⇒ Object

Returns an ActiveRecord::Result instance.



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# File 'lib/active_record/connection_adapters/teradata_adapter.rb', line 139

def select(sql, name = nil, binds = [])
  exec_query(sql, name)
end

#select_rows(sql, name = nil) ⇒ Object

Returns an array of arrays containing the field values. Order is the same as that returned by columns.



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# File 'lib/active_record/connection_adapters/teradata_adapter.rb', line 145

def select_rows(sql, name = nil)
  result = execute(sql, name)
  if result && result.count > 0
    result.entries.collect{|r|r.collect{|v|v}}
  else
    []
  end
end

#tables(name = nil) ⇒ Object

DATABASE STATEMENTS ======================================



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# File 'lib/active_record/connection_adapters/teradata_adapter.rb', line 104

def tables(name = nil)
  sql = "SELECT TABLENAME FROM DBC.TABLES "
  clauses = []
  clauses << "DATABASENAME = '#{@database}'" if @database
  clauses << "TABLENAME = '#{name}'" if name
  clauses << "TABLENAME LIKE '#{@table_name_prefix}%'" if @table_name_prefix
  unless clauses.empty?
    sql << " WHERE " + clauses.join(' AND ')
  end
  rs = execute(sql)
  rs.entries.collect {|record| record['TableName'].strip}
end