Class: ActiveRecord::ConnectionAdapters::TidbAdapter

Inherits:
Mysql2Adapter
  • Object
show all
Includes:
Sequence::Adapter
Defined in:
lib/active_record/connection_adapters/tidb_adapter.rb

Constant Summary collapse

ADAPTER_NAME = 
'Tidb'

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Sequence::Adapter

#check_sequences, #create_sequence, #drop_sequence, #recreate_sequence

Constructor Details

#initialize(connection, logger, conn_params, config) ⇒ TidbAdapter

Returns a new instance of TidbAdapter.



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

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

  tidb_version_string = query_value('select version()')
  @tidb_version = tidb_version_string[/TiDB-v([0-9.]+)/, 1]
end

Class Method Details

.database_exists?(config) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/tidb_adapter.rb', line 101

def self.database_exists?(config)
  !ActiveRecord::Base.tidb_connection(config).nil?
rescue ActiveRecord::NoDatabaseError
  false
end

Instance Method Details

#new_column_from_field(_table_name, field) ⇒ Object 



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# File 'lib/active_record/connection_adapters/tidb_adapter.rb', line 107

def new_column_from_field(_table_name, field)
  type_metadata = fetch_type_metadata(field[:Type], field[:Extra])
  default = field[:Default]
  default_function = nil

  if type_metadata.type == :datetime && /\ACURRENT_TIMESTAMP(?:\([0-6]?\))?\z/i.match?(default)
    default = "#{default} ON UPDATE #{default}" if /on update CURRENT_TIMESTAMP/i.match?(field[:Extra])
    default_function = default
    default = nil
  elsif type_metadata.extra == 'DEFAULT_GENERATED'
    default = +"(#{default})" unless default.start_with?('(')
    default_function = default
    default = nil
  elsif default.to_s =~ /nextval/i
    default_function = default
    default = nil
  end

  MySQL::Column.new(
    field[:Field],
    default,
    type_metadata,
    field[:Null] == 'YES',
    default_function,
    collation: field[:Collation],
    comment: field[:Comment].presence
  )
end

#supports_advisory_locks? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/tidb_adapter.rb', line 55

def supports_advisory_locks?
  # https://github.com/pingcap/tidb/issues/14994 support is required
  false
end

#supports_bulk_alter? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/tidb_adapter.rb', line 50

def supports_bulk_alter?
  # https://github.com/pingcap/tidb/issues/14766 support is required
  false
end

#supports_common_table_expressions? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/tidb_adapter.rb', line 82

def supports_common_table_expressions?
  tidb_version >= '5.1.0'
end

#supports_expression_index? ⇒ Boolean

Returns:

  • (Boolean) 


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

def supports_expression_index?
  sql = <<~SQL
    SELECT VALUE 
    FROM INFORMATION_SCHEMA.CLUSTER_CONFIG 
    WHERE `KEY` = 'experimental.allow-expression-index' AND `TYPE` = 'tidb'
  SQL
  query_value(sql) == 'true'
end

#supports_foreign_keys? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/tidb_adapter.rb', line 45

def supports_foreign_keys?
  # https://github.com/pingcap/tidb/issues/18209 support is required
  false
end

#supports_index_sort_order? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/tidb_adapter.rb', line 68

def supports_index_sort_order?
  # https://github.com/pingcap/tidb/issues/2519 support is required
  false
end

#supports_json? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/tidb_adapter.rb', line 64

def supports_json?
  true
end

#supports_optimizer_hints? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/tidb_adapter.rb', line 60

def supports_optimizer_hints?
  true
end

#supports_savepoints? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/tidb_adapter.rb', line 40

def supports_savepoints?
  # https://github.com/pingcap/tidb/issues/6840 support is required
  false
end

#tidb_version ⇒ Object 



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

def tidb_version
  Version.new(tidb_version_string)
end

#tidb_version_string ⇒ Object 



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# File 'lib/active_record/connection_adapters/tidb_adapter.rb', line 93

def tidb_version_string
  @tidb_version
end