Class: JDBCHelper::SequenceWrapper

Inherits:
ObjectWrapper show all
Defined in:
lib/jdbc-helper/wrapper/sequence_wrapper.rb

Overview

conn.sequence(:my_seq).drop!

Instance Attribute Summary

Attributes inherited from ObjectWrapper

#connection, #name

Instance Method Summary collapse

Constructor Details

#initialize(conn, name) ⇒ SequenceWrapper

Returns a new instance of SequenceWrapper.



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# File 'lib/jdbc-helper/wrapper/sequence_wrapper.rb', line 18

def initialize(conn, name)
  super conn, name

  case conn.driver
  when /postgres/
    @nextval_sql = "select nextval('#{name}')"
    @currval_sql = "select currval('#{name}')"
  else
    @nextval_sql = "select #{name}.nextval from dual"
    @currval_sql = "select #{name}.currval from dual"
  end
end

Instance Method Details

#create!(value = 1, increment_by = 1) ⇒ JDBCHelper::SequenceWrapper

Creates the sequence. Cannot be undone.

Parameters:

  • value (Fixnum) (defaults to: 1) —

    Initial value

  • increment_by (Fixnum) (defaults to: 1) —

    Increment size for a single nextval call

Returns:



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# File 'lib/jdbc-helper/wrapper/sequence_wrapper.rb', line 64

def create! value = 1, increment_by = 1
  create = JDBCHelper::SQL.check(
      "create sequence #{name} start with #{value} increment by #{increment_by}")
  @connection.update(create)
  self
end

#currval ⇒ Fixnum

Returns the incremented value of the sequence

Returns:

  • (Fixnum) 


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# File 'lib/jdbc-helper/wrapper/sequence_wrapper.rb', line 39

def currval
  @connection.query(@currval_sql).to_a[0][0].to_i
end

#drop! ⇒ JDBCHelper::SequenceWrapper

Drops the sequence. Cannot be undone.

Returns:



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# File 'lib/jdbc-helper/wrapper/sequence_wrapper.rb', line 55

def drop!
  @connection.update("drop sequence #{name}")
  self
end

#nextval ⇒ Fixnum

Increments the sequence and returns the value

Returns:

  • (Fixnum) 


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# File 'lib/jdbc-helper/wrapper/sequence_wrapper.rb', line 33

def nextval
  @connection.query(@nextval_sql).to_a[0][0].to_i
end

#reset!(value = 1, increment_by = 1) ⇒ JDBCHelper::SequenceWrapper

Recreates the sequence. Cannot be undone.

Parameters:

  • value (Fixnum) (defaults to: 1) —

    Initial value

  • increment_by (Fixnum) (defaults to: 1) —

    Increment size for a single nextval call

Returns:



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# File 'lib/jdbc-helper/wrapper/sequence_wrapper.rb', line 47

def reset! value = 1, increment_by = 1
  drop! rescue nil
  create! value, increment_by
  self
end