# module ActiveRecord::ConnectionAdapters::DatabaseLimits

### Public Instance Methods

allowed_index_name_length() click to toggle source

Returns the maximum allowed length for an index name. This limit is enforced by Rails and is less than or equal to index_name_length. The gap between index_name_length is to allow internal Rails operations to use prefixes in temporary operations.

    # File lib/active_record/connection_adapters/abstract/database_limits.rb, line 24
    def allowed_index_name_length
      index_name_length
    end

column_name_length() click to toggle source

Returns the maximum length of a column name.

    # File lib/active_record/connection_adapters/abstract/database_limits.rb, line 10
    def column_name_length
      64
    end

columns_per_multicolumn_index() click to toggle source

Returns the maximum number of columns in a multicolumn index.

    # File lib/active_record/connection_adapters/abstract/database_limits.rb, line 44
    def columns_per_multicolumn_index
      16
    end

columns_per_table() click to toggle source

Returns the maximum number of columns per table.

    # File lib/active_record/connection_adapters/abstract/database_limits.rb, line 34
    def columns_per_table
      1024
    end

in_clause_length() click to toggle source

Returns the maximum number of elements in an IN (x,y,z) clause. `nil` means no limit.

    # File lib/active_record/connection_adapters/abstract/database_limits.rb, line 50
    def in_clause_length
      nil
    end

index_name_length() click to toggle source

Returns the maximum length of an index name.

    # File lib/active_record/connection_adapters/abstract/database_limits.rb, line 29
    def index_name_length
      64
    end

indexes_per_table() click to toggle source

Returns the maximum number of indexes per table.

    # File lib/active_record/connection_adapters/abstract/database_limits.rb, line 39
    def indexes_per_table
      16
    end

joins_per_query() click to toggle source

Returns maximum number of joins in a single query.

    # File lib/active_record/connection_adapters/abstract/database_limits.rb, line 60
    def joins_per_query
      256
    end

sql_query_length() click to toggle source

Returns the maximum length of an SQL query.

    # File lib/active_record/connection_adapters/abstract/database_limits.rb, line 55
    def sql_query_length
      1048575
    end

table_alias_length() click to toggle source

Returns the maximum length of a table alias.

    # File lib/active_record/connection_adapters/abstract/database_limits.rb, line 5
    def table_alias_length
      255
    end

table_name_length() click to toggle source

Returns the maximum length of a table name.

    # File lib/active_record/connection_adapters/abstract/database_limits.rb, line 15
    def table_name_length
      64
    end