Class: ActiveRecord::ConnectionAdapters::AbstractMysqlAdapter

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

Direct Known Subclasses

Mysql2Adapter

Defined Under Namespace

Classes: MysqlString, StatementPool

Constant Summary collapse

NATIVE_DATABASE_TYPES = 
{
  primary_key: "bigint auto_increment PRIMARY KEY",
  string:      { name: "varchar", limit: 255 },
  text:        { name: "text" },
  integer:     { name: "int", limit: 4 },
  float:       { name: "float", limit: 24 },
  decimal:     { name: "decimal" },
  datetime:    { name: "datetime" },
  timestamp:   { name: "timestamp" },
  time:        { name: "time" },
  date:        { name: "date" },
  binary:      { name: "blob" },
  blob:        { name: "blob" },
  boolean:     { name: "tinyint", limit: 1 },
  json:        { name: "json" },
}

Constants inherited from AbstractAdapter

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

Instance Attribute Summary

Attributes inherited from AbstractAdapter

#lock, #logger, #owner, #pool, #visitor

Attributes included from QueryCache

#query_cache, #query_cache_enabled

Attributes included from DatabaseStatements

#transaction_manager

Instance Method Summary collapse

Methods included from MySQL::SchemaStatements

#create_schema_dumper, #create_table, #indexes, #internal_string_options_for_primary_key, #remove_column, #table_alias_length, #type_to_sql, #update_table_definition

Methods included from MySQL::Quoting

#column_name_matcher, #column_name_with_order_matcher, #quote_column_name, #quote_table_name, #quoted_binary, #quoted_date, #unquoted_false, #unquoted_true

Methods inherited from AbstractAdapter

#active?, #adapter_name, #advisory_locks_enabled?, build_read_query_regexp, #case_insensitive_comparison, #close, #column_name_for_operation, database_exists?, #database_version, #disable_extension, #discard!, #disconnect!, #enable_extension, #expire, #extensions, #lease, #migration_context, #migrations_paths, #prefetch_primary_key?, #prepared_statements, #prepared_statements_disabled_cache, #preventing_writes?, quoted_column_names, quoted_table_names, #raw_connection, #reconnect!, #replica?, #requires_reloading?, #reset!, #schema_cache, #schema_cache=, #schema_migration, #seconds_idle, #steal!, #supports_comments?, #supports_comments_in_create?, #supports_ddl_transactions?, #supports_extensions?, #supports_foreign_keys_in_create?, #supports_foreign_tables?, #supports_insert_conflict_target?, #supports_insert_returning?, #supports_json?, #supports_lazy_transactions?, #supports_materialized_views?, #supports_multi_insert?, #supports_partial_index?, #supports_partitioned_indexes?, #supports_savepoints?, #supports_validate_constraints?, type_cast_config_to_boolean, type_cast_config_to_integer, #unprepared_statement, #valid_type?, #verify!

Methods included from Savepoints

#create_savepoint, #current_savepoint_name, #exec_rollback_to_savepoint, #release_savepoint

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, #max_identifier_length, #sql_query_length, #table_alias_length, #table_name_length

Methods included from Quoting

#column_name_matcher, #column_name_with_order_matcher, #lookup_cast_type_from_column, #quote, #quote_column_name, #quote_default_expression, #quote_string, #quote_table_name, #quote_table_name_for_assignment, #quoted_binary, #quoted_date, #quoted_false, #quoted_time, #quoted_true, #sanitize_as_sql_comment, #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_insert_all, #exec_query, #exec_update, #insert, #insert_fixture, #insert_fixtures_set, #query, #query_value, #query_values, #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, #truncate, #truncate_tables, #update, #with_yaml_fallback, #write_query?

Methods included from SchemaStatements

#add_column, #add_foreign_key, #add_index_options, #add_reference, #add_timestamps, #assume_migrated_upto_version, #change_table, #column_exists?, #columns, #create_join_table, #create_schema_dumper, #create_table, #data_source_exists?, #data_sources, #drop_join_table, #dump_schema_information, #foreign_key_column_for, #foreign_key_exists?, #foreign_key_options, #index_exists?, #index_name, #index_name_exists?, #indexes, #internal_string_options_for_primary_key, #options_include_default?, #primary_key, #remove_column, #remove_columns, #remove_foreign_key, #remove_index, #remove_reference, #remove_timestamps, #table_alias_for, #table_exists?, #tables, #type_to_sql, #update_table_definition, #view_exists?, #views

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 53

def initialize(connection, logger, connection_options, config)
  super(connection, logger, config)
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 368

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 374

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

#begin_db_transaction ⇒ Object 



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 213

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 217

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

#build_insert_sql(insert) ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 512

def build_insert_sql(insert) # :nodoc:
  sql = +"INSERT #{insert.into} #{insert.values_list}"

  if insert.skip_duplicates?
    no_op_column = quote_column_name(insert.keys.first)
    sql << " ON DUPLICATE KEY UPDATE #{no_op_column}=#{no_op_column}"
  elsif insert.update_duplicates?
    sql << " ON DUPLICATE KEY UPDATE "
    sql << insert.updatable_columns.map { |column| "#{column}=VALUES(#{column})" }.join(",")
  end

  sql
end

#case_sensitive_comparison(attribute, value) ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 474

def case_sensitive_comparison(attribute, value) # :nodoc:
  column = column_for_attribute(attribute)

  if column.collation && !column.case_sensitive?
    attribute.eq(Arel::Nodes::Bin.new(value))
  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 359

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

#change_column_comment(table_name, column_name, comment_or_changes) ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 354

def change_column_comment(table_name, column_name, comment_or_changes) # :nodoc:
  comment = extract_new_comment_value(comment_or_changes)
  change_column table_name, column_name, nil, comment: comment
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 341

def change_column_default(table_name, column_name, default_or_changes) #:nodoc:
  default = extract_new_default_value(default_or_changes)
  change_column table_name, column_name, nil, 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 346

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

#change_table_comment(table_name, comment_or_changes) ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 297

def change_table_comment(table_name, comment_or_changes) # :nodoc:
  comment = extract_new_comment_value(comment_or_changes)
  comment = "" if comment.nil?
  execute("ALTER TABLE #{quote_table_name(table_name)} COMMENT #{quote(comment)}")
end

#charset ⇒ Object

Returns the database character set.



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 277

def charset
  show_variable "character_set_database"
end

#check_version ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 526

def check_version # :nodoc:
  if database_version < "5.5.8"
    raise "Your version of MySQL (#{database_version}) is too old. Active Record supports MySQL >= 5.5.8."
  end
end

#clear_cache! ⇒ Object

CONNECTION MANAGEMENT ====================================



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 177

def clear_cache! # :nodoc:
  reload_type_map
  super
end

#collation ⇒ Object

Returns the database collation strategy.



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 282

def collation
  show_variable "collation_database"
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 493

def columns_for_distinct(columns, orders) # :nodoc:
  order_columns = orders.reject(&:blank?).map { |s|
    # Convert Arel node to string
    s = visitor.compile(s) 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}" }

  (order_columns << super).join(", ")
end

#commit_db_transaction ⇒ Object

:nodoc:



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

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 utf8mb4.

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 252

def create_database(name, options = {})
  if options[:collation]
    execute "CREATE DATABASE #{quote_table_name(name)} DEFAULT COLLATE #{quote_table_name(options[:collation])}"
  elsif options[:charset]
    execute "CREATE DATABASE #{quote_table_name(name)} DEFAULT CHARACTER SET #{quote_table_name(options[:charset])}"
  elsif row_format_dynamic_by_default?
    execute "CREATE DATABASE #{quote_table_name(name)} DEFAULT CHARACTER SET `utf8mb4`"
  else
    raise "Configure a supported :charset and ensure innodb_large_prefix is enabled to support indexes on varchar(255) string columns."
  end
end

#current_database ⇒ Object 



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 272

def current_database
  query_value("SELECT database()", "SCHEMA")
end

#default_index_type?(index) ⇒ Boolean

:nodoc:

Returns:

  • (Boolean) 


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

def default_index_type?(index) # :nodoc:
  index.using == :btree || super
end

#default_uniqueness_comparison(attribute, value, klass) ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 459

def default_uniqueness_comparison(attribute, value, klass) # :nodoc:
  column = column_for_attribute(attribute)

  if column.collation && !column.case_sensitive? && !value.nil?
    ActiveSupport::Deprecation.warn(<<~MSG.squish)
      Uniqueness validator will no longer enforce case sensitive comparison in Rails 6.1.
      To continue case sensitive comparison on the :#{attribute.name} attribute in #{klass} model,
      pass `case_sensitive: true` option explicitly to the uniqueness validator.
    MSG
    attribute.eq(Arel::Nodes::Bin.new(value))
  else
    super
  end
end

#disable_referential_integrity ⇒ Object

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



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 164

def disable_referential_integrity #:nodoc:
  old = query_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 268

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 327

def drop_table(table_name, options = {})
  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 152

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

#empty_insert_statement_value(primary_key = nil) ⇒ Object 



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 230

def empty_insert_statement_value(primary_key = nil)
  "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 27

class_attribute :emulate_booleans, default: true

#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 158

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 226

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 196

def execute(sql, name = nil)
  materialize_transactions

  log(sql, name) do
    ActiveSupport::Dependencies.interlock.permit_concurrent_loads do
      @connection.query(sql)
    end
  end
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 209

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 186

def explain(arel, binds = [])
  sql     = "EXPLAIN #{to_sql(arel, binds)}"
  start   = Concurrent.monotonic_time
  result  = exec_query(sql, "EXPLAIN", binds)
  elapsed = Concurrent.monotonic_time - 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 379

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

  scope = quoted_scope(table_name)

  fk_info = exec_query(<<~SQL, "SCHEMA")
    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',
           rc.update_rule AS 'on_update',
           rc.delete_rule AS 'on_delete'
    FROM information_schema.referential_constraints rc
    JOIN information_schema.key_column_usage fk
    USING (constraint_schema, constraint_name)
    WHERE fk.referenced_column_name IS NOT NULL
      AND fk.table_schema = #{scope[:schema]}
      AND fk.table_name = #{scope[:name]}
      AND rc.constraint_schema = #{scope[:schema]}
      AND rc.table_name = #{scope[:name]}
  SQL

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

    options[:on_update] = extract_foreign_key_action(row["on_update"])
    options[:on_delete] = extract_foreign_key_action(row["on_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 132

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

#get_database_version ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 57

def get_database_version #:nodoc:
  full_version_string = get_full_version
  version_string = version_string(full_version_string)
  Version.new(version_string, full_version_string)
end

#index_algorithms ⇒ Object 



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

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

#mariadb? ⇒ Boolean

:nodoc:

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 63

def mariadb? # :nodoc:
  /mariadb/i.match?(full_version)
end

#native_database_types ⇒ Object 



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

def native_database_types
  NATIVE_DATABASE_TYPES
end

#primary_keys(table_name) ⇒ Object

:nodoc:

Raises:

  • (ArgumentError) 


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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 444

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

  scope = quoted_scope(table_name)

  query_values(<<~SQL, "SCHEMA")
    SELECT column_name
    FROM information_schema.statistics
    WHERE index_name = 'PRIMARY'
      AND table_schema = #{scope[:schema]}
      AND table_name = #{scope[:name]}
    ORDER BY seq_in_index
  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 238

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 136

def release_advisory_lock(lock_name) # :nodoc:
  query_value("SELECT RELEASE_LOCK(#{quote(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 363

def rename_column(table_name, column_name, new_column_name) #:nodoc:
  execute("ALTER TABLE #{quote_table_name(table_name)} #{rename_column_for_alter(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 331

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 307

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

#show_variable(name) ⇒ Object

SHOW VARIABLES LIKE ‘name’



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 438

def show_variable(name)
  query_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 504

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 120

def supports_advisory_locks?
  true
end

#supports_bulk_alter? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 67

def supports_bulk_alter?
  true
end

#supports_common_table_expressions? ⇒ Boolean

Returns:

  • (Boolean) 


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

def supports_common_table_expressions?
  if mariadb?
    database_version >= "10.2.1"
  else
    database_version >= "8.0.1"
  end
end

#supports_datetime_with_precision? ⇒ Boolean

Returns:

  • (Boolean) 


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

def supports_datetime_with_precision?
  mariadb? || database_version >= "5.6.4"
end

#supports_explain? ⇒ Boolean

Returns:

  • (Boolean) 


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

def supports_explain?
  true
end

#supports_expression_index? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 75

def supports_expression_index?
  !mariadb? && database_version >= "8.0.13"
end

#supports_foreign_keys? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 91

def supports_foreign_keys?
  true
end

#supports_index_sort_order? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 71

def supports_index_sort_order?
  !mariadb? && database_version >= "8.0.1"
end

#supports_indexes_in_create? ⇒ Boolean

Returns:

  • (Boolean) 


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

def supports_indexes_in_create?
  true
end

#supports_insert_on_duplicate_skip? ⇒ Boolean

Returns:

  • (Boolean) 


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

def supports_insert_on_duplicate_skip?
  true
end

#supports_insert_on_duplicate_update? ⇒ Boolean

Returns:

  • (Boolean) 


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

def supports_insert_on_duplicate_update?
  true
end

#supports_optimizer_hints? ⇒ Boolean

See dev.mysql.com/doc/refman/8.0/en/optimizer-hints.html for more details.

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 108

def supports_optimizer_hints?
  !mariadb? && database_version >= "5.7.7"
end

#supports_transaction_isolation? ⇒ Boolean

Returns:

  • (Boolean) 


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

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 95

def supports_views?
  true
end

#supports_virtual_columns? ⇒ Boolean

Returns:

  • (Boolean) 


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

def supports_virtual_columns?
  mariadb? || database_version >= "5.7.5"
end

#table_comment(table_name) ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 286

def table_comment(table_name) # :nodoc:
  scope = quoted_scope(table_name)

  query_value(<<~SQL, "SCHEMA").presence
    SELECT table_comment
    FROM information_schema.tables
    WHERE table_schema = #{scope[:schema]}
      AND table_name = #{scope[:name]}
  SQL
end

#table_options(table_name) ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/abstract_mysql_adapter.rb', line 415

def table_options(table_name) # :nodoc:
  table_options = {}

  create_table_info = create_table_info(table_name)

  # strip create_definitions and partition_options
  # Be aware that `create_table_info` might not include any table options due to `NO_TABLE_OPTIONS` sql mode.
  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')

  table_options[:options] = raw_table_options unless raw_table_options.blank?

  # strip COMMENT
  if raw_table_options.sub!(/ COMMENT='.+'/, "")
    table_options[:comment] = table_comment(table_name)
  end

  table_options
end