Module: ActiveRecord::ConnectionAdapters::DatabaseStatements

Included in:
AbstractAdapter
Defined in:
lib/active_record/connection_adapters/abstract/database_statements.rb

Instance Method Summary collapse

Instance Method Details

#add_limit!(sql, options) ⇒ Object

Alias for add_limit_offset!.



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# File 'lib/active_record/connection_adapters/abstract/database_statements.rb', line 97

def add_limit!(sql, options)
  add_limit_offset!(sql, options) if options
end

#add_limit_offset!(sql, options) ⇒ Object

Appends LIMIT and OFFSET options to an SQL statement, or some SQL fragment that has the same semantics as LIMIT and OFFSET.

options must be a Hash which contains a :limit option (required) and an :offset option (optional).

This method modifies the sql parameter.

Examples
add_limit_offset!('SELECT * FROM suppliers', {:limit => 10, :offset => 50})

generates

SELECT * FROM suppliers LIMIT 10 OFFSET 50



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# File 'lib/active_record/connection_adapters/abstract/database_statements.rb', line 113

def add_limit_offset!(sql, options)
  if limit = options[:limit]
    sql << " LIMIT #{sanitize_limit(limit)}"
    if offset = options[:offset]
      sql << " OFFSET #{offset.to_i}"
    end
  end
  sql
end

#add_lock!(sql, options) ⇒ Object

Appends a locking clause to an SQL statement. This method modifies the sql parameter.

# SELECT * FROM suppliers FOR UPDATE
add_lock! 'SELECT * FROM suppliers', :lock => true
add_lock! 'SELECT * FROM suppliers', :lock => ' FOR UPDATE'



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# File 'lib/active_record/connection_adapters/abstract/database_statements.rb', line 128

def add_lock!(sql, options)
  case lock = options[:lock]
    when true;   sql << ' FOR UPDATE'
    when String; sql << " #{lock}"
  end
end

#begin_db_transaction ⇒ Object

Begins the transaction (and turns off auto-committing).



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# File 'lib/active_record/connection_adapters/abstract/database_statements.rb', line 87

def begin_db_transaction()    end

#case_sensitive_equality_operator ⇒ Object 



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

def case_sensitive_equality_operator
  "="
end

#commit_db_transaction ⇒ Object

Commits the transaction (and turns on auto-committing).



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# File 'lib/active_record/connection_adapters/abstract/database_statements.rb', line 90

def commit_db_transaction()   end

#default_sequence_name(table, column) ⇒ Object 



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# File 'lib/active_record/connection_adapters/abstract/database_statements.rb', line 135

def default_sequence_name(table, column)
  nil
end

#delete(sql, name = nil) ⇒ Object

Executes the delete statement and returns the number of rows affected.



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# File 'lib/active_record/connection_adapters/abstract/database_statements.rb', line 53

def delete(sql, name = nil)
  delete_sql(sql, name)
end

#empty_insert_statement(table_name) ⇒ Object 



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# File 'lib/active_record/connection_adapters/abstract/database_statements.rb', line 150

def empty_insert_statement(table_name)
  "INSERT INTO #{quote_table_name(table_name)} VALUES(DEFAULT)"
end

#execute(sql, name = nil) ⇒ Object

Executes the SQL statement in the context of this connection.

Raises:

  • (NotImplementedError) 


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# File 'lib/active_record/connection_adapters/abstract/database_statements.rb', line 38

def execute(sql, name = nil)
  raise NotImplementedError, "execute is an abstract method"
end

#insert(sql, name = nil, pk = nil, id_value = nil, sequence_name = nil) ⇒ Object

Returns the last auto-generated ID from the affected table.



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# File 'lib/active_record/connection_adapters/abstract/database_statements.rb', line 43

def insert(sql, name = nil, pk = nil, id_value = nil, sequence_name = nil)
  insert_sql(sql, name, pk, id_value, sequence_name)
end

#insert_fixture(fixture, table_name) ⇒ Object

Inserts the given fixture into the table. Overridden in adapters that require something beyond a simple insert (eg. Oracle).



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# File 'lib/active_record/connection_adapters/abstract/database_statements.rb', line 146

def insert_fixture(fixture, table_name)
  execute "INSERT INTO #{quote_table_name(table_name)} (#{fixture.key_list}) VALUES (#{fixture.value_list})", 'Fixture Insert'
end

#limited_update_conditions(where_sql, quoted_table_name, quoted_primary_key) ⇒ Object 



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

def limited_update_conditions(where_sql, quoted_table_name, quoted_primary_key)
  "WHERE #{quoted_primary_key} IN (SELECT #{quoted_primary_key} FROM #{quoted_table_name} #{where_sql})"
end

#reset_sequence!(table, column, sequence = nil) ⇒ Object

Set the sequence to the max value of the table’s column.



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# File 'lib/active_record/connection_adapters/abstract/database_statements.rb', line 140

def reset_sequence!(table, column, sequence = nil)
  # Do nothing by default.  Implement for PostgreSQL, Oracle, ...
end

#rollback_db_transaction ⇒ Object

Rolls back the transaction (and turns on auto-committing). Must be done if the transaction block raises an exception or returns false.



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

def rollback_db_transaction() end

#select_all(sql, name = nil) ⇒ Object

Returns an array of record hashes with the column names as keys and column values as values.



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# File 'lib/active_record/connection_adapters/abstract/database_statements.rb', line 6

def select_all(sql, name = nil)
  select(sql, name)
end

#select_one(sql, name = nil) ⇒ Object

Returns a record hash with the column names as keys and column values as values.



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# File 'lib/active_record/connection_adapters/abstract/database_statements.rb', line 12

def select_one(sql, name = nil)
  result = select_all(sql, name)
  result.first if result
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.

Raises:

  • (NotImplementedError) 


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# File 'lib/active_record/connection_adapters/abstract/database_statements.rb', line 33

def select_rows(sql, name = nil)
  raise NotImplementedError, "select_rows is an abstract method"
end

#select_value(sql, name = nil) ⇒ Object

Returns a single value from a record



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# File 'lib/active_record/connection_adapters/abstract/database_statements.rb', line 18

def select_value(sql, name = nil)
  if result = select_one(sql, name)
    result.values.first
  end
end

#select_values(sql, name = nil) ⇒ Object

Returns an array of the values of the first column in a select:

select_values("SELECT id FROM companies LIMIT 3") => [1,2,3]



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# File 'lib/active_record/connection_adapters/abstract/database_statements.rb', line 26

def select_values(sql, name = nil)
  result = select_rows(sql, name)
  result.map { |v| v[0] }
end

#transaction(start_db_transaction = true) ⇒ Object

Wrap a block in a transaction. Returns result of block.



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# File 'lib/active_record/connection_adapters/abstract/database_statements.rb', line 58

def transaction(start_db_transaction = true)
  transaction_open = false
  begin
    if block_given?
      if start_db_transaction
        begin_db_transaction
        transaction_open = true
      end
      yield
    end
  rescue Exception => database_transaction_rollback
    if transaction_open
      transaction_open = false
      rollback_db_transaction
    end
    raise unless database_transaction_rollback.is_a? ActiveRecord::Rollback
  end
ensure
  if transaction_open
    begin
      commit_db_transaction
    rescue Exception => database_transaction_rollback
      rollback_db_transaction
      raise
    end
  end
end

#update(sql, name = nil) ⇒ Object

Executes the update statement and returns the number of rows affected.



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# File 'lib/active_record/connection_adapters/abstract/database_statements.rb', line 48

def update(sql, name = nil)
  update_sql(sql, name)
end