instance method `primary_key`

Ruby on Rails 3.1.12

Since v2.3.18 Last seen in v3.2.22.5

Available in: v2.3.18 v3.0.20 v3.1.12 v3.2.22.5

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primary_key(table)

Returns just a table’s primary key

Parameters

table req

Source

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 934
      def primary_key(table)
        row = exec_query(<<-end_sql, 'SCHEMA', [[nil, table]]).rows.first
          SELECT DISTINCT(attr.attname)
          FROM pg_attribute attr
          INNER JOIN pg_depend dep ON attr.attrelid = dep.refobjid AND attr.attnum = dep.refobjsubid
          INNER JOIN pg_constraint cons ON attr.attrelid = cons.conrelid AND attr.attnum = cons.conkey[1]
          WHERE cons.contype = 'p'
            AND dep.refobjid = $1::regclass
        end_sql

        row && row.first
      end

Defined in activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb line 934 · View on GitHub · Improve this page · Find usages on GitHub

Defined in ActiveRecord::ConnectionAdapters::PostgreSQLAdapter

Signature

Parameters