Class: FlexiRecord::LockMode

Inherits:
Object
  • Object
show all
Defined in:
lib/flexirecord.rb

Overview

Table lock modes are represented by (constant) LockMode objects:

  • LockMode::AccessShare (Acquired by any read operation.)

  • LockMode::RowShare (Acquired for any row-locking operation.)

  • LockMode::RowExclusive (Acquired when data in a table is modified.)

  • LockMode::ShareUpdateExclusive

  • LockMode::Share (Prohibits data changes in the table.)

  • LockMode::ShareRowExclusive (Prohibits data changes and other Share or ShareRowExclusive locks. Used instead of LockMode::Share to prohibit dead locks, where two processes holding share locks want to write to a table.)

  • LockMode::Exclusive (Prohibits anything else than reading from the table.)

  • LockMode::AccessExclusive (Prohibits any other access to the table.)

Constant Summary collapse

AccessShare = 
new(:access_share,           'ACCESS SHARE MODE',           'AccessShare')
RowShare = 
new(:row_share,              'ROW SHARE MODE',              'RowShare')
RowExclusive = 
new(:row_exclusive,          'ROW EXCLUSIVE MODE',          'RowExclusive')
ShareUpdateExclusive = 
new(:share_update_exclusive, 'SHARE UPDATE EXCLUSIVE MODE', 'ShareUpdateExclusive')
Share = 
new(:share,                  'SHARE MODE',                  'Share')
ShareRowExclusive = 
new(:share_row_exclusive,    'SHARE ROW EXCLUSIVE MODE',    'ShareRowExclusive')
Exclusive = 
new(:exclusive,              'EXCLUSIVE MODE',              'Exclusive')
AccessExclusive = 
new(:access_exclusive,       'ACCESS EXCLUSIVE MODE',       'AccessExclusive')
@@symbols = 
{}

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(symbol, sql, name) ⇒ LockMode

Used for generating the constants representing the possible table lock modes.



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# File 'lib/flexirecord.rb', line 143

def initialize(symbol, sql, name)
  @symbol  = symbol.to_sym
  @sql     = sql.to_s.dup.freeze
  @name    = name.to_s.dup.freeze
  @@symbols[@symbol] = self
  nil
end

Class Method Details

.by_symbol(symbol) ⇒ Object

Returns a LockMode object, matching the given symbol.



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# File 'lib/flexirecord.rb', line 138

def self.by_symbol(symbol)
  @@symbols[symbol.to_sym]
end

Instance Method Details

#inspect ⇒ Object

Returns the name of the constant referring to the lock mode.



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# File 'lib/flexirecord.rb', line 157

def inspect
  "#{self.class.name}::#{@name}"
end

#to_s ⇒ Object

Returns the SQL string representation of the lock mode.



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# File 'lib/flexirecord.rb', line 152

def to_s
  @sql
end