Module: Sequel::MySQL::DatabaseMethods

Overview

Methods shared by Database instances that connect to MySQL, currently supported by the native and JDBC adapters.

Constant Summary

AUTO_INCREMENT =
'AUTO_INCREMENT'.freeze
CAST_TYPES =
{String=>:CHAR, Integer=>:SIGNED, Time=>:DATETIME, DateTime=>:DATETIME, Numeric=>:DECIMAL, BigDecimal=>:DECIMAL, File=>:BINARY}
COLUMN_DEFINITION_ORDER =
[:collate, :null, :default, :unique, :primary_key, :auto_increment, :references]
PRIMARY =
'PRIMARY'.freeze
MYSQL_TIMESTAMP_RE =
/\ACURRENT_(?:DATE|TIMESTAMP)?\z/

Instance Method Summary collapse

Methods included from Database::ResetIdentifierMangling

extended

Instance Method Details

#cast_type_literal(type) ⇒ Object

MySQL's cast rules are restrictive in that you can't just cast to any possible database type.



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# File 'lib/sequel/adapters/shared/mysql.rb', line 47

def cast_type_literal(type)
  CAST_TYPES[type] || super
end

#commit_prepared_transaction(transaction_id, opts = OPTS) ⇒ Object

Commit an existing prepared transaction with the given transaction identifier string.



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# File 'lib/sequel/adapters/shared/mysql.rb', line 53

def commit_prepared_transaction(transaction_id, opts=OPTS)
  run("XA COMMIT #{literal(transaction_id)}", opts)
end

#database_typeObject

MySQL uses the :mysql database type



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# File 'lib/sequel/adapters/shared/mysql.rb', line 58

def database_type
  :mysql
end

#foreign_key_list(table, opts = OPTS) ⇒ Object

Use the Information Schema's KEY_COLUMN_USAGE table to get basic information on foreign key columns, but include the constraint name.



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# File 'lib/sequel/adapters/shared/mysql.rb', line 65

def foreign_key_list(table, opts=OPTS)
  m = output_identifier_meth
  im = input_identifier_meth
  ds = .
    from(:INFORMATION_SCHEMA__KEY_COLUMN_USAGE).
    where(:TABLE_NAME=>im.call(table), :TABLE_SCHEMA=>Sequel.function(:DATABASE)).
    exclude(:CONSTRAINT_NAME=>'PRIMARY').
    exclude(:REFERENCED_TABLE_NAME=>nil).
    select(:CONSTRAINT_NAME___name, :COLUMN_NAME___column, :REFERENCED_TABLE_NAME___table, :REFERENCED_COLUMN_NAME___key)
  
  h = {}
  ds.each do |row|
    if r = h[row[:name]]
      r[:columns] << m.call(row[:column])
      r[:key] << m.call(row[:key])
    else
      h[row[:name]] = {:name=>m.call(row[:name]), :columns=>[m.call(row[:column])], :table=>m.call(row[:table]), :key=>[m.call(row[:key])]}
    end
  end
  h.values
end

#global_index_namespace?Boolean

MySQL namespaces indexes per table.

Returns:

  • (Boolean)


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# File 'lib/sequel/adapters/shared/mysql.rb', line 88

def global_index_namespace?
  false
end

#indexes(table, opts = OPTS) ⇒ Object

Use SHOW INDEX FROM to get the index information for the table.

By default partial indexes are not included, you can use the option :partial to override this.



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# File 'lib/sequel/adapters/shared/mysql.rb', line 97

def indexes(table, opts=OPTS)
  indexes = {}
  remove_indexes = []
  m = output_identifier_meth
  im = input_identifier_meth
  .with_sql("SHOW INDEX FROM ?", SQL::Identifier.new(im.call(table))).each do |r|
    name = r[:Key_name]
    next if name == PRIMARY
    name = m.call(name)
    remove_indexes << name if r[:Sub_part] && ! opts[:partial]
    i = indexes[name] ||= {:columns=>[], :unique=>r[:Non_unique] != 1}
    i[:columns] << m.call(r[:Column_name])
  end
  indexes.reject{|k,v| remove_indexes.include?(k)}
end

#rollback_prepared_transaction(transaction_id, opts = OPTS) ⇒ Object

Rollback an existing prepared transaction with the given transaction identifier string.



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# File 'lib/sequel/adapters/shared/mysql.rb', line 115

def rollback_prepared_transaction(transaction_id, opts=OPTS)
  run("XA ROLLBACK #{literal(transaction_id)}", opts)
end

#server_versionObject

Get version of MySQL server, used for determined capabilities.



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# File 'lib/sequel/adapters/shared/mysql.rb', line 120

def server_version
  @server_version ||= begin
    m = /(\d+)\.(\d+)\.(\d+)/.match(get(SQL::Function.new(:version)))
    (m[1].to_i * 10000) + (m[2].to_i * 100) + m[3].to_i
  end
end

#supports_create_table_if_not_exists?Boolean

MySQL supports CREATE TABLE IF NOT EXISTS syntax.

Returns:

  • (Boolean)


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# File 'lib/sequel/adapters/shared/mysql.rb', line 128

def supports_create_table_if_not_exists?
  true
end

#supports_prepared_transactions?Boolean

MySQL 5+ supports prepared transactions (two-phase commit) using XA

Returns:

  • (Boolean)


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# File 'lib/sequel/adapters/shared/mysql.rb', line 133

def supports_prepared_transactions?
  server_version >= 50000
end

#supports_savepoints?Boolean

MySQL 5+ supports savepoints

Returns:

  • (Boolean)


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# File 'lib/sequel/adapters/shared/mysql.rb', line 138

def supports_savepoints?
  server_version >= 50000
end

#supports_savepoints_in_prepared_transactions?Boolean

MySQL doesn't support savepoints inside prepared transactions in from 5.5.12 to 5.5.23, see bugs.mysql.com/bug.php?id=64374

Returns:

  • (Boolean)


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# File 'lib/sequel/adapters/shared/mysql.rb', line 144

def supports_savepoints_in_prepared_transactions?
  super && (server_version <= 50512 || server_version >= 50523)
end

#supports_timestamp_usecs?Boolean

Support fractional timestamps on MySQL 5.6.5+ if the :fractional_seconds Database option is used. Technically, MySQL 5.6.4+ supports them, but automatic initialization of datetime values wasn't supported to 5.6.5+, and this is related to that.

Returns:

  • (Boolean)


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# File 'lib/sequel/adapters/shared/mysql.rb', line 152

def supports_timestamp_usecs?
  @supports_timestamp_usecs ||= server_version >= 50605 && typecast_value_boolean(opts[:fractional_seconds])
end

#supports_transaction_isolation_levels?Boolean

MySQL supports transaction isolation levels

Returns:

  • (Boolean)


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# File 'lib/sequel/adapters/shared/mysql.rb', line 157

def supports_transaction_isolation_levels?
  true
end

#tables(opts = OPTS) ⇒ Object

Return an array of symbols specifying table names in the current database.

Options:

:server

Set the server to use



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# File 'lib/sequel/adapters/shared/mysql.rb', line 165

def tables(opts=OPTS)
  full_tables('BASE TABLE', opts)
end

#use(db_name) ⇒ Object

Changes the database in use by issuing a USE statement. I would be very careful if I used this.



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# File 'lib/sequel/adapters/shared/mysql.rb', line 171

def use(db_name)
  disconnect
  @opts[:database] = db_name if self << "USE #{db_name}"
  @schemas = {}
  self
end

#views(opts = OPTS) ⇒ Object

Return an array of symbols specifying view names in the current database.

Options:

:server

Set the server to use



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# File 'lib/sequel/adapters/shared/mysql.rb', line 182

def views(opts=OPTS)
  full_tables('VIEW', opts)
end