Class: ActiveRecord::ConnectionAdapters::AbstractMysqlAdapter

Inherits:
AbstractAdapter
  • Object
show all
Includes:
MySQL::ColumnDumper, MySQL::Quoting
Defined in:
lib/active_record/connection_adapters/abstract_mysql_adapter.rb

Direct Known Subclasses

Mysql2Adapter

Defined Under Namespace

Classes: MysqlJson, MysqlString, StatementPool

Constant Summary collapse

NATIVE_DATABASE_TYPES = 
{
  primary_key: "int auto_increment PRIMARY KEY",
  string:      { name: "varchar", limit: 255 },
  text:        { name: "text" },
  integer:     { name: "int", limit: 4 },
  float:       { name: "float" },
  decimal:     { name: "decimal" },
  datetime:    { name: "datetime" },
  time:        { name: "time" },
  date:        { name: "date" },
  binary:      { name: "blob" },
  boolean:     { name: "tinyint", limit: 1 },
  json:        { name: "json" },
}
INDEX_TYPES = 
[:fulltext, :spatial]
INDEX_USINGS = 
[:btree, :hash]
CHARSETS_OF_4BYTES_MAXLEN = 
['utf8mb4', 'utf16', 'utf16le', 'utf32']

Constants inherited from AbstractAdapter

ActiveRecord::ConnectionAdapters::AbstractAdapter::ADAPTER_NAME, ActiveRecord::ConnectionAdapters::AbstractAdapter::SIMPLE_INT

Instance Attribute Summary

Attributes inherited from AbstractAdapter

#logger, #owner, #pool, #prepared_statements, #schema_cache, #visitor

Attributes included from QueryCache

#query_cache, #query_cache_enabled

Attributes included from DatabaseStatements

#transaction_manager

Instance Method Summary collapse

Methods included from MySQL::ColumnDumper

#column_spec_for_primary_key, #migration_keys, #prepare_column_options

Methods included from MySQL::Quoting

#quote_column_name, #quote_table_name, #quoted_date, #quoted_false, #quoted_true, #unquoted_false, #unquoted_true

Methods inherited from AbstractAdapter

#active?, #adapter_name, #case_insensitive_comparison, #close, #collector, #column_name_for_operation, #combine_bind_parameters, #disable_extension, #disconnect!, #enable_extension, #expire, #extensions, #lease, #lookup_cast_type, #prefetch_primary_key?, #raw_connection, #reconnect!, #requires_reloading?, #reset!, #supports_comments?, #supports_comments_in_create?, #supports_ddl_transactions?, #supports_expression_index?, #supports_extensions?, #supports_json?, #supports_multi_insert?, #supports_partial_index?, #supports_savepoints?, type_cast_config_to_boolean, type_cast_config_to_integer, #type_map, #unprepared_statement, #verify!

Methods included from Savepoints

#create_savepoint, #current_savepoint_name, #exec_rollback_to_savepoint, #release_savepoint

Methods included from ColumnDumper

#column_spec, #column_spec_for_primary_key, #migration_keys, #prepare_column_options

Methods included from QueryCache

#cache, #clear_query_cache, dirties_query_cache, #disable_query_cache!, #enable_query_cache!, included, #select_all, #uncached

Methods included from DatabaseLimits

#allowed_index_name_length, #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 Quoting

#lookup_cast_type_from_column, #prepare_binds_for_database, #quote, #quote_column_name, #quote_default_expression, #quote_string, #quote_table_name, #quote_table_name_for_assignment, #quoted_date, #quoted_false, #quoted_time, #quoted_true, #type_cast, #type_cast_from_column, #unquoted_false, #unquoted_true

Methods included from DatabaseStatements

#add_transaction_record, #cacheable_query, #default_sequence_name, #delete, #exec_delete, #exec_insert, #exec_query, #exec_update, #insert, #insert_fixture, #reset_sequence!, #reset_transaction, #rollback_db_transaction, #rollback_to_savepoint, #sanitize_limit, #select_all, #select_one, #select_rows, #select_value, #select_values, #to_sql, #transaction, #transaction_isolation_levels, #transaction_open?, #transaction_state, #update

Methods included from SchemaStatements

#add_column, #add_foreign_key, #add_index_options, #add_reference, #add_timestamps, #assume_migrated_upto_version, #change_column_comment, #change_table, #change_table_comment, #column_exists?, #create_join_table, #drop_join_table, #dump_schema_information, #foreign_key_column_for, #foreign_key_exists?, #foreign_key_for, #foreign_key_for!, #foreign_key_options, #index_exists?, #index_name, #index_name_exists?, #initialize_internal_metadata_table, #initialize_schema_migrations_table, #insert_versions_sql, #options_include_default?, #primary_key, #remove_column, #remove_columns, #remove_foreign_key, #remove_index, #remove_reference, #remove_timestamps, #table_alias_for

Constructor Details

#initialize(connection, logger, connection_options, config) ⇒ AbstractMysqlAdapter

Returns a new instance of AbstractMysqlAdapter.



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 65

def initialize(connection, logger, connection_options, config)
  super(connection, logger, config)

  @statements = StatementPool.new(self.class.type_cast_config_to_integer(config[:statement_limit]))

  if version < '5.0.0'
    raise "Your version of MySQL (#{full_version.match(/^\d+\.\d+\.\d+/)[0]}) is too old. Active Record supports MySQL >= 5.0."
  end
end

Instance Method Details

#add_index(table_name, column_name, options = {}) ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 502

def add_index(table_name, column_name, options = {}) #:nodoc:
  index_name, index_type, index_columns, _, index_algorithm, index_using, comment = add_index_options(table_name, column_name, options)
  sql = "CREATE #{index_type} INDEX #{quote_column_name(index_name)} #{index_using} ON #{quote_table_name(table_name)} (#{index_columns}) #{index_algorithm}"
  execute add_sql_comment!(sql, comment)
end

#add_sql_comment!(sql, comment) ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 508

def add_sql_comment!(sql, comment) # :nodoc:
  sql << " COMMENT #{quote(comment)}" if comment
  sql
end

#arel_visitor ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 27

def arel_visitor # :nodoc:
  Arel::Visitors::MySQL.new(self)
end

#begin_db_transaction ⇒ Object 



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

def begin_db_transaction
  execute "BEGIN"
end

#begin_isolated_db_transaction(isolation) ⇒ Object 



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

def begin_isolated_db_transaction(isolation)
  execute "SET TRANSACTION ISOLATION LEVEL #{transaction_isolation_levels.fetch(isolation)}"
  begin_db_transaction
end

#bulk_change_table(table_name, operations) ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 423

def bulk_change_table(table_name, operations) #:nodoc:
  sqls = operations.flat_map do |command, args|
    table, arguments = args.shift, args
    method = :"#{command}_sql"

    if respond_to?(method, true)
      send(method, table, *arguments)
    else
      raise "Unknown method called : #{method}(#{arguments.inspect})"
    end
  end.join(", ")

  execute("ALTER TABLE #{quote_table_name(table_name)} #{sqls}")
end

#case_sensitive_comparison(table, attribute, column, value) ⇒ Object 



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 605

def case_sensitive_comparison(table, attribute, column, value)
  if !value.nil? && column.collation && !column.case_sensitive?
    table[attribute].eq(Arel::Nodes::Bin.new(Arel::Nodes::BindParam.new))
  else
    super
  end
end

#change_column(table_name, column_name, type, options = {}) ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 493

def change_column(table_name, column_name, type, options = {}) #:nodoc:
  execute("ALTER TABLE #{quote_table_name(table_name)} #{change_column_sql(table_name, column_name, type, options)}")
end

#change_column_default(table_name, column_name, default_or_changes) ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 477

def change_column_default(table_name, column_name, default_or_changes) #:nodoc:
  default = extract_new_default_value(default_or_changes)
  column = column_for(table_name, column_name)
  change_column table_name, column_name, column.sql_type, :default => default
end

#change_column_null(table_name, column_name, null, default = nil) ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 483

def change_column_null(table_name, column_name, null, default = nil) #:nodoc:
  column = column_for(table_name, column_name)

  unless null || default.nil?
    execute("UPDATE #{quote_table_name(table_name)} SET #{quote_column_name(column_name)}=#{quote(default)} WHERE #{quote_column_name(column_name)} IS NULL")
  end

  change_column table_name, column_name, column.sql_type, :null => null
end

#charset ⇒ Object

Returns the database character set.



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 300

def charset
  show_variable 'character_set_database'
end

#clear_cache! ⇒ Object

Clears the prepared statements cache.



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

def clear_cache!
  reload_type_map
  @statements.clear
end

#collation ⇒ Object

Returns the database collation strategy.



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 305

def collation
  show_variable 'collation_database'
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/abstract_mysql_adapter.rb', line 398

def columns(table_name) # :nodoc:
  table_name = table_name.to_s
  column_definitions(table_name).map do |field|
    type_metadata = fetch_type_metadata(field[:Type], field[:Extra])
    if type_metadata.type == :datetime && field[:Default] == "CURRENT_TIMESTAMP"
      default, default_function = nil, field[:Default]
    else
      default, default_function = field[:Default], nil
    end
    new_column(field[:Field], default, type_metadata, field[:Null] == "YES", table_name, default_function, field[:Collation], comment: field[:Comment].presence)
  end
end

#columns_for_distinct(columns, orders) ⇒ Object

In MySQL 5.7.5 and up, ONLY_FULL_GROUP_BY affects handling of queries that use DISTINCT and ORDER BY. It requires the ORDER BY columns in the select list for distinct queries, and requires that the ORDER BY include the distinct column. See dev.mysql.com/doc/refman/5.7/en/group-by-handling.html



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 622

def columns_for_distinct(columns, orders) # :nodoc:
  order_columns = orders.reject(&:blank?).map { |s|
    # Convert Arel node to string
    s = s.to_sql unless s.is_a?(String)
    # Remove any ASC/DESC modifiers
    s.gsub(/\s+(?:ASC|DESC)\b/i, '')
  }.reject(&:blank?).map.with_index { |column, i| "#{column} AS alias_#{i}" }

  [super, *order_columns].join(', ')
end

#commit_db_transaction ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 237

def commit_db_transaction #:nodoc:
  execute "COMMIT"
end

#create_database(name, options = {}) ⇒ Object

Create a new MySQL database with optional :charset and :collation. Charset defaults to utf8.

Example:

create_database 'charset_test', charset: 'latin1', collation: 'latin1_bin'
create_database 'matt_development'
create_database 'matt_development', charset: :big5



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 279

def create_database(name, options = {})
  if options[:collation]
    execute "CREATE DATABASE #{quote_table_name(name)} DEFAULT CHARACTER SET #{quote_table_name(options[:charset] || 'utf8')} COLLATE #{quote_table_name(options[:collation])}"
  else
    execute "CREATE DATABASE #{quote_table_name(name)} DEFAULT CHARACTER SET #{quote_table_name(options[:charset] || 'utf8')}"
  end
end

#create_table(table_name, **options) ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 419

def create_table(table_name, **options) #:nodoc:
  super(table_name, options: 'ENGINE=InnoDB', **options)
end

#current_database ⇒ Object 



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 295

def current_database
  select_value 'SELECT DATABASE() as db'
end

#data_source_exists?(table_name) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 347

def data_source_exists?(table_name)
  return false unless table_name.present?

  schema, name = extract_schema_qualified_name(table_name)

  sql = "SELECT table_name FROM information_schema.tables "
  sql << "WHERE table_schema = #{quote(schema)} AND table_name = #{quote(name)}"

  select_values(sql, 'SCHEMA').any?
end

#data_sources ⇒ Object 



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 325

def data_sources
  sql = "SELECT table_name FROM information_schema.tables "
  sql << "WHERE table_schema = #{quote(@config[:database])}"

  select_values(sql, 'SCHEMA')
end

#disable_referential_integrity ⇒ Object

REFERENTIAL INTEGRITY ====================================



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 184

def disable_referential_integrity #:nodoc:
  old = select_value("SELECT @@FOREIGN_KEY_CHECKS")

  begin
    update("SET FOREIGN_KEY_CHECKS = 0")
    yield
  ensure
    update("SET FOREIGN_KEY_CHECKS = #{old}")
  end
end

#drop_database(name) ⇒ Object

Drops a MySQL database.

Example:

drop_database('sebastian_development')



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 291

def drop_database(name) #:nodoc:
  execute "DROP DATABASE IF EXISTS #{quote_table_name(name)}"
end

#drop_table(table_name, options = {}) ⇒ Object

Drops a table from the database.

:force

Set to :cascade to drop dependent objects as well. Defaults to false.

:if_exists

Set to true to only drop the table if it exists. Defaults to false.

:temporary

Set to true to drop temporary table. Defaults to false.

Although this command ignores most options and the block if one is given, it can be helpful to provide these in a migration’s change method so it can be reverted. In that case, options and the block will be used by create_table.



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 462

def drop_table(table_name, options = {})
  create_table_info_cache.delete(table_name) if create_table_info_cache.key?(table_name)
  execute "DROP#{' TEMPORARY' if options[:temporary]} TABLE#{' IF EXISTS' if options[:if_exists]} #{quote_table_name(table_name)}#{' CASCADE' if options[:force] == :cascade}"
end

#each_hash(result) ⇒ Object

The two drivers have slightly different ways of yielding hashes of results, so this method must be implemented to provide a uniform interface.

Raises:

  • (NotImplementedError) 


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

def each_hash(result) # :nodoc:
  raise NotImplementedError
end

#empty_insert_statement_value ⇒ Object 



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 257

def empty_insert_statement_value
  "VALUES ()"
end

#emulate_booleans ⇒ Object

:singleton-method: By default, the Mysql2Adapter will consider all columns of type tinyint(1) as boolean. If you wish to disable this emulation you can add the following line to your application.rb file:

ActiveRecord::ConnectionAdapters::Mysql2Adapter.emulate_booleans = false



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

class_attribute :emulate_booleans

#error_number(exception) ⇒ Object

Must return the MySQL error number from the exception, if the exception has an error number.

Raises:

  • (NotImplementedError) 


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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 178

def error_number(exception) # :nodoc:
  raise NotImplementedError
end

#exec_rollback_db_transaction ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 241

def exec_rollback_db_transaction #:nodoc:
  execute "ROLLBACK"
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/abstract_mysql_adapter.rb', line 217

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

#execute_and_free(sql, name = nil) {|execute(sql, name)| ... } ⇒ Object

Mysql2Adapter doesn’t have to free a result after using it, but we use this method to write stuff in an abstract way without concerning ourselves about whether it needs to be explicitly freed or not.

Yields:



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 224

def execute_and_free(sql, name = nil) # :nodoc:
  yield execute(sql, name)
end

#explain(arel, binds = []) ⇒ Object

– DATABASE STATEMENTS ====================================== ++



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

def explain(arel, binds = [])
  sql     = "EXPLAIN #{to_sql(arel, binds)}"
  start   = Time.now
  result  = exec_query(sql, 'EXPLAIN', binds)
  elapsed = Time.now - start

  MySQL::ExplainPrettyPrinter.new.pp(result, elapsed)
end

#foreign_keys(table_name) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 513

def foreign_keys(table_name)
  raise ArgumentError unless table_name.present?

  schema, name = extract_schema_qualified_name(table_name)

  fk_info = select_all <<-SQL.strip_heredoc
    SELECT fk.referenced_table_name as 'to_table'
          ,fk.referenced_column_name as 'primary_key'
          ,fk.column_name as 'column'
          ,fk.constraint_name as 'name'
    FROM information_schema.key_column_usage fk
    WHERE fk.referenced_column_name is not null
      AND fk.table_schema = #{quote(schema)}
      AND fk.table_name = #{quote(name)}
  SQL

  create_table_info = create_table_info(table_name)

  fk_info.map do |row|
    options = {
      column: row['column'],
      name: row['name'],
      primary_key: row['primary_key']
    }

    options[:on_update] = extract_foreign_key_action(create_table_info, row['name'], "UPDATE")
    options[:on_delete] = extract_foreign_key_action(create_table_info, row['name'], "DELETE")

    ForeignKeyDefinition.new(table_name, row['to_table'], options)
  end
end

#get_advisory_lock(lock_name, timeout = 0) ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 148

def get_advisory_lock(lock_name, timeout = 0) # :nodoc:
  select_value("SELECT GET_LOCK('#{lock_name}', #{timeout});").to_s == '1'
end

#index_algorithms ⇒ Object 



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 160

def index_algorithms
  { default: 'ALGORITHM = DEFAULT', copy: 'ALGORITHM = COPY', inplace: 'ALGORITHM = INPLACE' }
end

#indexes(table_name, name = nil) ⇒ Object

Returns an array of indexes for the given table.



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 374

def indexes(table_name, name = nil) #:nodoc:
  indexes = []
  current_index = nil
  execute_and_free("SHOW KEYS FROM #{quote_table_name(table_name)}", 'SCHEMA') do |result|
    each_hash(result) do |row|
      if current_index != row[:Key_name]
        next if row[:Key_name] == 'PRIMARY' # skip the primary key
        current_index = row[:Key_name]

        mysql_index_type = row[:Index_type].downcase.to_sym
        index_type  = INDEX_TYPES.include?(mysql_index_type)  ? mysql_index_type : nil
        index_using = INDEX_USINGS.include?(mysql_index_type) ? mysql_index_type : nil
        indexes << IndexDefinition.new(row[:Table], row[:Key_name], row[:Non_unique].to_i == 0, [], [], nil, nil, index_type, index_using, row[:Index_comment].presence)
      end

      indexes.last.columns << row[:Column_name]
      indexes.last.lengths << row[:Sub_part]
    end
  end

  indexes
end

#internal_string_options_for_primary_key ⇒ Object

:nodoc:



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

def internal_string_options_for_primary_key # :nodoc:
  super.tap { |options|
    options[:collation] = collation.sub(/\A[^_]+/, 'utf8') if CHARSETS_OF_4BYTES_MAXLEN.include?(charset)
  }
end

#join_to_update(update, select, key) ⇒ Object

In the simple case, MySQL allows us to place JOINs directly into the UPDATE query. However, this does not allow for LIMIT, OFFSET and ORDER. To support these, we must use a subquery.



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 248

def join_to_update(update, select, key) # :nodoc:
  if select.limit || select.offset || select.orders.any?
    super
  else
    update.table select.source
    update.wheres = select.constraints
  end
end

#mariadb? ⇒ Boolean

:nodoc:

Returns:

  • (Boolean) 


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

def mariadb? # :nodoc:
  full_version =~ /mariadb/i
end

#native_database_types ⇒ Object 



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 156

def native_database_types
  NATIVE_DATABASE_TYPES
end

#new_column(*args) ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 172

def new_column(*args) #:nodoc:
  MySQL::Column.new(*args)
end

#primary_keys(table_name) ⇒ Object

:nodoc:

Raises:

  • (ArgumentError) 


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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 590

def primary_keys(table_name) # :nodoc:
  raise ArgumentError unless table_name.present?

  schema, name = extract_schema_qualified_name(table_name)

  select_values(<<-SQL.strip_heredoc, 'SCHEMA')
    SELECT column_name
    FROM information_schema.key_column_usage
    WHERE constraint_name = 'PRIMARY'
      AND table_schema = #{quote(schema)}
      AND table_name = #{quote(name)}
    ORDER BY ordinal_position
  SQL
end

#recreate_database(name, options = {}) ⇒ Object

Drops the database specified on the name attribute and creates it again using the provided options.



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 265

def recreate_database(name, options = {})
  drop_database(name)
  sql = create_database(name, options)
  reconnect!
  sql
end

#release_advisory_lock(lock_name) ⇒ Object

:nodoc:



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

def release_advisory_lock(lock_name) # :nodoc:
  select_value("SELECT RELEASE_LOCK('#{lock_name}')").to_s == '1'
end

#rename_column(table_name, column_name, new_column_name) ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 497

def rename_column(table_name, column_name, new_column_name) #:nodoc:
  execute("ALTER TABLE #{quote_table_name(table_name)} #{rename_column_sql(table_name, column_name, new_column_name)}")
  rename_column_indexes(table_name, column_name, new_column_name)
end

#rename_index(table_name, old_name, new_name) ⇒ Object 



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 467

def rename_index(table_name, old_name, new_name)
  if supports_rename_index?
    validate_index_length!(table_name, new_name)

    execute "ALTER TABLE #{quote_table_name(table_name)} RENAME INDEX #{quote_table_name(old_name)} TO #{quote_table_name(new_name)}"
  else
    super
  end
end

#rename_table(table_name, new_name) ⇒ Object

Renames a table.

Example:

rename_table('octopuses', 'octopi')



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 442

def rename_table(table_name, new_name)
  execute "RENAME TABLE #{quote_table_name(table_name)} TO #{quote_table_name(new_name)}"
  rename_table_indexes(table_name, new_name)
end

#schema_creation ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 23

def schema_creation # :nodoc:
  MySQL::SchemaCreation.new(self)
end

#show_variable(name) ⇒ Object

SHOW VARIABLES LIKE ‘name’



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 584

def show_variable(name)
  select_value("SELECT @@#{name}", 'SCHEMA')
rescue ActiveRecord::StatementInvalid
  nil
end

#strict_mode? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 633

def strict_mode?
  self.class.type_cast_config_to_boolean(@config.fetch(:strict, true))
end

#supports_advisory_locks? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 144

def supports_advisory_locks?
  true
end

#supports_bulk_alter? ⇒ Boolean

:nodoc:

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 100

def supports_bulk_alter? #:nodoc:
  true
end

#supports_datetime_with_precision? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 136

def supports_datetime_with_precision?
  if mariadb?
    version >= '5.3.0'
  else
    version >= '5.6.4'
  end
end

#supports_explain? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 120

def supports_explain?
  true
end

#supports_foreign_keys? ⇒ Boolean

Returns:

  • (Boolean) 


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

def supports_foreign_keys?
  true
end

#supports_index_sort_order? ⇒ Boolean

Technically MySQL allows to create indexes with the sort order syntax but at the moment (5.5) it doesn’t yet implement them

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 112

def supports_index_sort_order?
  true
end

#supports_indexes_in_create? ⇒ Boolean

Returns:

  • (Boolean) 


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

def supports_indexes_in_create?
  true
end

#supports_migrations? ⇒ Boolean

Returns true, since this connection adapter supports migrations.

Returns:

  • (Boolean) 


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

def supports_migrations?
  true
end

#supports_primary_key? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 96

def supports_primary_key?
  true
end

#supports_statement_cache? ⇒ Boolean

Returns true, since this connection adapter supports prepared statement caching.

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 106

def supports_statement_cache?
  true
end

#supports_transaction_isolation? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 116

def supports_transaction_isolation?
  true
end

#supports_views? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 132

def supports_views?
  true
end

#table_comment(table_name) ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 411

def table_comment(table_name) # :nodoc:
  select_value(<<-SQL.strip_heredoc, 'SCHEMA')
    SELECT table_comment
    FROM information_schema.tables
    WHERE table_name=#{quote(table_name)}
  SQL
end

#table_exists?(table_name) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 336

def table_exists?(table_name)
  # Update lib/active_record/internal_metadata.rb when this gets removed
  ActiveSupport::Deprecation.warn(<<-MSG.squish)
    #table_exists? currently checks both tables and views.
    This behavior is deprecated and will be changed with Rails 5.1 to only check tables.
    Use #data_source_exists? instead.
  MSG

  data_source_exists?(table_name)
end

#table_options(table_name) ⇒ Object 



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 545

def table_options(table_name)
  create_table_info = create_table_info(table_name)

  # strip create_definitions and partition_options
  raw_table_options = create_table_info.sub(/\A.*\n\) /m, '').sub(/\n\/\*!.*\*\/\n\z/m, '').strip

  # strip AUTO_INCREMENT
  raw_table_options.sub!(/(ENGINE=\w+)(?: AUTO_INCREMENT=\d+)/, '\1')

  # strip COMMENT
  raw_table_options.sub!(/ COMMENT='.+'/, '')

  raw_table_options
end

#tables(name = nil) ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 309

def tables(name = nil) # :nodoc:
  ActiveSupport::Deprecation.warn(<<-MSG.squish)
    #tables currently returns both tables and views.
    This behavior is deprecated and will be changed with Rails 5.1 to only return tables.
    Use #data_sources instead.
  MSG

  if name
    ActiveSupport::Deprecation.warn(<<-MSG.squish)
      Passing arguments to #tables is deprecated without replacement.
    MSG
  end

  data_sources
end

#truncate(table_name, name = nil) ⇒ Object 



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 332

def truncate(table_name, name = nil)
  execute "TRUNCATE TABLE #{quote_table_name(table_name)}", name
end

#type_to_sql(type, limit = nil, precision = nil, scale = nil, unsigned = nil) ⇒ Object

Maps logical Rails types to MySQL-specific data types.



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 561

def type_to_sql(type, limit = nil, precision = nil, scale = nil, unsigned = nil)
  sql = case type.to_s
  when 'integer'
    integer_to_sql(limit)
  when 'text'
    text_to_sql(limit)
  when 'blob'
    binary_to_sql(limit)
  when 'binary'
    if (0..0xfff) === limit
      "varbinary(#{limit})"
    else
      binary_to_sql(limit)
    end
  else
    super(type, limit, precision, scale)
  end

  sql << ' unsigned' if unsigned && type != :primary_key
  sql
end

#update_table_definition(table_name, base) ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 19

def update_table_definition(table_name, base) # :nodoc:
  MySQL::Table.new(table_name, base)
end

#valid_type?(type) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 637

def valid_type?(type)
  !native_database_types[type].nil?
end

#version ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 83

def version #:nodoc:
  @version ||= Version.new(full_version.match(/^\d+\.\d+\.\d+/)[0])
end

#view_exists?(view_name) ⇒ Boolean

:nodoc:

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 362

def view_exists?(view_name) # :nodoc:
  return false unless view_name.present?

  schema, name = extract_schema_qualified_name(view_name)

  sql = "SELECT table_name FROM information_schema.tables WHERE table_type = 'VIEW'"
  sql << " AND table_schema = #{quote(schema)} AND table_name = #{quote(name)}"

  select_values(sql, 'SCHEMA').any?
end

#views ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 358

def views # :nodoc:
  select_values("SHOW FULL TABLES WHERE table_type = 'VIEW'", 'SCHEMA')
end