Class: ActiveRecord::ConnectionAdapters::AbstractAdapter

Inherits:

Object

• Object
• ActiveRecord::ConnectionAdapters::AbstractAdapter

show all

Includes:

DatabaseLimits, DatabaseStatements, Quoting, SchemaStatements, QueryCache, ActiveSupport::Callbacks

Defined in:

activerecord/lib/active_record/connection_adapters/abstract_adapter.rb

Overview

Instance Attribute Summary (collapse)

• - (Object) visitor

  Returns the value of attribute visitor.

Class Method Summary (collapse)

• + (Object) visitor_for(pool)

  Returns a visitor instance for this adaptor, which conforms to the Arel::ToSql interface.

Instance Method Summary (collapse)

• - (Boolean) active?

  Checks whether the connection to the database is still active.

• - (Object) adapter_name

  Returns the human-readable name of the adapter.

• - (Object) case_sensitive_modifier(node)
• - (Object) clear_cache!

  Clear any caching the database adapter may be doing, for example clearing the prepared statement cache.

• - (Object) create_savepoint
• - (Object) current_savepoint_name
• - (Object) decrement_open_transactions
• - (Object) disable_referential_integrity

  Override to turn off referential integrity while executing &block.

• - (Object) disconnect!

  Disconnects from the database if already connected.

• - (Object) increment_open_transactions
• - (AbstractAdapter) initialize(connection, logger = nil) constructor

  :nodoc:.

• - (Object) open_transactions
• - (Boolean) prefetch_primary_key?(table_name = nil)

  Should primary key values be selected from their corresponding sequence before the insert statement? If true, next_sequence_value is called before each insert to set the record's primary key.

• - (Object) quote_table_name(name)

  Override to return the quoted table name.

• - (Object) raw_connection

  Provides access to the underlying database driver for this adapter.

• - (Object) reconnect!

  Disconnects from the database if already connected, and establishes a new connection with the database.

• - (Object) release_savepoint
• - (Boolean) requires_reloading?

  Returns true if its required to reload the connection between requests for development mode.

• - (Object) reset!

  Reset the state of this connection, directing the DBMS to clear transactions and other connection-related server-side state.

• - (Object) rollback_to_savepoint
• - (Object) substitute_at(column, index)

  Returns a bind substitution value given a column and list of current binds.

• - (Boolean) supports_bulk_alter?
• - (Boolean) supports_count_distinct?

  Does this adapter support using DISTINCT within COUNT? This is true for all adapters except sqlite.

• - (Boolean) supports_ddl_transactions?

  Does this adapter support DDL rollbacks in transactions? That is, would CREATE TABLE or ALTER TABLE get rolled back by a transaction? PostgreSQL, SQL Server, and others support this.

• - (Boolean) supports_migrations?

  Does this adapter support migrations? Backend specific, as the abstract adapter always returns false.

• - (Boolean) supports_primary_key?

  Can this adapter determine the primary key for tables not attached to an Active Record class, such as join tables? Backend specific, as the abstract adapter always returns false.

• - (Boolean) supports_savepoints?

  Does this adapter support savepoints? PostgreSQL and MySQL do, SQLite < 3.6.8 does not.

• - (Object) transaction_joinable=(joinable)
• - (Object) verify!(*ignored)

  Checks whether the connection to the database is still active (i.e. not stale).

Methods included from ActiveSupport::Callbacks

#run_callbacks

Methods included from ActiveSupport::Concern

#append_features, extended, #included

Methods inherited from QueryCache

#call

Methods included from DatabaseLimits

#column_name_length, #columns_per_multicolumn_index, #columns_per_table, #in_clause_length, #index_name_length, #indexes_per_table, #joins_per_query, #sql_query_length, #table_alias_length, #table_name_length

Methods included from SchemaStatements

#add_column, #add_column_options!, #add_index, #add_timestamps, #assume_migrated_upto_version, #change_column, #change_column_default, #change_table, #column_exists?, #columns, #create_table, #distinct, #drop_table, #dump_schema_information, #index_exists?, #index_name, #index_name_exists?, #initialize_schema_migrations_table, #native_database_types, #remove_column, #remove_index, #remove_index!, #remove_timestamps, #rename_column, #rename_index, #rename_table, #structure_dump, #table_alias_for, #table_exists?, #type_to_sql

Methods included from DatabaseStatements

#add_limit_offset!, #add_transaction_record, #begin_db_transaction, #case_sensitive_equality_operator, #commit_db_transaction, #default_sequence_name, #delete, #empty_insert_statement_value, #exec_delete, #exec_insert, #exec_query, #exec_update, #execute, #insert, #insert_fixture, #join_to_update, #limited_update_conditions, #outside_transaction?, #reset_sequence!, #rollback_db_transaction, #sanitize_limit, #select_all, #select_one, #select_rows, #select_value, #select_values, #supports_statement_cache?, #to_sql, #transaction, #update

Methods included from Quoting

#quote, #quote_column_name, #quote_string, #quoted_date, #quoted_false, #quoted_true, #type_cast

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# File 'activerecord/lib/active_record/connection_adapters/abstract_adapter.rb', line 44

def initialize(connection, logger = nil) #:nodoc:
  @active = nil
  @connection, @logger = connection, logger
  @query_cache_enabled = false
  @query_cache = Hash.new { |h,sql| h[sql] = {} }
  @instrumenter = ActiveSupport::Notifications.instrumenter
  @visitor = nil
end

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# File 'activerecord/lib/active_record/connection_adapters/abstract_adapter.rb', line 42

def visitor
  @visitor
end

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# File 'activerecord/lib/active_record/connection_adapters/abstract_adapter.rb', line 54

def self.visitor_for(pool) # :nodoc:
  adapter = pool.spec.config[:adapter]

  if Arel::Visitors::VISITORS[adapter]
    ActiveSupport::Deprecation.warn(
      "Arel::Visitors::VISITORS is deprecated and will be removed. Database adapters " \
      "should define a visitor_for method which returns the appropriate visitor for " \
      "the database. For example, MysqlAdapter.visitor_for(pool) returns " \
      "Arel::Visitors::MySQL.new(pool)."
    )

    Arel::Visitors::VISITORS[adapter].new(pool)
  else
    Arel::Visitors::ToSql.new(pool)
  end
end

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# File 'activerecord/lib/active_record/connection_adapters/abstract_adapter.rb', line 146

def active?
  @active != false
end

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# File 'activerecord/lib/active_record/connection_adapters/abstract_adapter.rb', line 73

def adapter_name
  'Abstract'
end

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# File 'activerecord/lib/active_record/connection_adapters/abstract_adapter.rb', line 228

def case_sensitive_modifier(node)
  node
end

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# File 'activerecord/lib/active_record/connection_adapters/abstract_adapter.rb', line 175

def clear_cache!
  # this should be overridden by concrete adapters
end

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# File 'activerecord/lib/active_record/connection_adapters/abstract_adapter.rb', line 219

def create_savepoint
end

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# File 'activerecord/lib/active_record/connection_adapters/abstract_adapter.rb', line 232

def current_savepoint_name
  "active_record_#{open_transactions}"
end

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# File 'activerecord/lib/active_record/connection_adapters/abstract_adapter.rb', line 211

def decrement_open_transactions
  @open_transactions -= 1
end

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# File 'activerecord/lib/active_record/connection_adapters/abstract_adapter.rb', line 137

def disable_referential_integrity
  yield
end

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

def disconnect!
  @active = false
end

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# File 'activerecord/lib/active_record/connection_adapters/abstract_adapter.rb', line 206

def increment_open_transactions
  @open_transactions ||= 0
  @open_transactions += 1
end

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# File 'activerecord/lib/active_record/connection_adapters/abstract_adapter.rb', line 202

def open_transactions
  @open_transactions ||= 0
end

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# File 'activerecord/lib/active_record/connection_adapters/abstract_adapter.rb', line 117

def prefetch_primary_key?(table_name = nil)
  false
end

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# File 'activerecord/lib/active_record/connection_adapters/abstract_adapter.rb', line 124

def quote_table_name(name)
  quote_column_name(name)
end

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# File 'activerecord/lib/active_record/connection_adapters/abstract_adapter.rb', line 198

def raw_connection
  @connection
end

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# File 'activerecord/lib/active_record/connection_adapters/abstract_adapter.rb', line 152

def reconnect!
  @active = true
end

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# File 'activerecord/lib/active_record/connection_adapters/abstract_adapter.rb', line 225

def release_savepoint
end

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# File 'activerecord/lib/active_record/connection_adapters/abstract_adapter.rb', line 181

def requires_reloading?
  false
end

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# File 'activerecord/lib/active_record/connection_adapters/abstract_adapter.rb', line 168

def reset!
  # this should be overridden by concrete adapters
end

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# File 'activerecord/lib/active_record/connection_adapters/abstract_adapter.rb', line 222

def rollback_to_savepoint
end

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# File 'activerecord/lib/active_record/connection_adapters/abstract_adapter.rb', line 130

def substitute_at(column, index)
  Arel.sql '?'
end

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# File 'activerecord/lib/active_record/connection_adapters/abstract_adapter.rb', line 103

def supports_bulk_alter?
  false
end

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# File 'activerecord/lib/active_record/connection_adapters/abstract_adapter.rb', line 92

def supports_count_distinct?
  true
end

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# File 'activerecord/lib/active_record/connection_adapters/abstract_adapter.rb', line 99

def supports_ddl_transactions?
  false
end

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# File 'activerecord/lib/active_record/connection_adapters/abstract_adapter.rb', line 79

def supports_migrations?
  false
end

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# File 'activerecord/lib/active_record/connection_adapters/abstract_adapter.rb', line 86

def supports_primary_key?
  false
end

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# File 'activerecord/lib/active_record/connection_adapters/abstract_adapter.rb', line 109

def supports_savepoints?
  false
end

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# File 'activerecord/lib/active_record/connection_adapters/abstract_adapter.rb', line 215

def transaction_joinable=(joinable)
  @transaction_joinable = joinable
end

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# File 'activerecord/lib/active_record/connection_adapters/abstract_adapter.rb', line 188

def verify!(*ignored)
  reconnect! unless active?
end