Module: SchemaPlusPgIndexes::Middleware::Postgresql::Schema::Indexes

Defined in:
lib/schema_plus_pg_indexes/middleware/postgresql/schema.rb

Instance Method Summary collapse

Instance Method Details

#get_opclass_names(env, opclasses) ⇒ Object 



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# File 'lib/schema_plus_pg_indexes/middleware/postgresql/schema.rb', line 7

def get_opclass_names(env, opclasses)
  @opclass_names ||= {}
  if (missing = opclasses - @opclass_names.keys).any?
    result = env.connection.query("    SELECT oid, opcname FROM pg_opclass\n    WHERE (NOT opcdefault) AND oid IN (\#{opclasses.join(',')})\n    SQL\n    result.each do |oid, opcname|\n      @opclass_names[oid] = opcname\n    end\n  end\nend\n", 'SCHEMA')

#implement(env) ⇒ Object 



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# File 'lib/schema_plus_pg_indexes/middleware/postgresql/schema.rb', line 20

def implement(env)
  # Ideally we'd let AR do its stuff and then add the extras.
  #
  # But one of the extras is expressions.  AR completely strips out
  # indexes with expressions, so to handle them we need to
  # essentially reissue the original query and then duplicate what
  # AR does to process them.  That being the case we may as well
  # just skip AR's implementation and use ours.
  #
  # We could limit that query to just those indexes that have
  # expressions, but we'd still have our code duplicating the AR
  # code.  Plus, our own query can handle operator classess at the
  # same time, but to add operator_classes to AR's definitions we'd
  # still have to issue additional queries.  Plus, using our own
  # query we have the opportunity to handle tables of the form
  # 'namespace.tablename'
  #
  # So, this replacs the AR implementation

  result = env.connection.query("    SELECT distinct i.relname, d.indisunique, d.indkey, pg_get_indexdef(d.indexrelid), t.oid,\n            m.amname, pg_get_expr(d.indpred, t.oid) as conditions, pg_get_expr(d.indexprs, t.oid) as expression,\n            d.indclass\n    FROM pg_class t\n    INNER JOIN pg_index d ON t.oid = d.indrelid\n    INNER JOIN pg_class i ON d.indexrelid = i.oid\n    INNER JOIN pg_am m ON i.relam = m.oid\n    WHERE i.relkind = 'i'\n      AND d.indisprimary = 'f'\n      AND t.relname = '\#{table_name_without_namespace(env.table_name)}'\n      AND i.relnamespace IN (SELECT oid FROM pg_namespace WHERE nspname = \#{namespace_sql(env.table_name)} )\n    ORDER BY i.relname\n  SQL\n\n  env.index_definitions += result.map do |(index_name, unique, indkey, inddef, oid, using, conditions, expression, indclass)|\n    index_keys = indkey.split(\" \")\n    opclasses = indclass.split(\" \")\n\n    rows = env.connection.query(<<-SQL, 'SCHEMA')\n      SELECT CAST(a.attnum as VARCHAR), a.attname, t.typname\n      FROM pg_attribute a\n      INNER JOIN pg_type t ON a.atttypid = t.oid\n      WHERE a.attrelid = \#{oid}\n    SQL\n    columns = {}\n    types = {}\n    rows.each do |num, name, type|\n      columns[num] = name\n      types[name] = type\n    end\n\n    column_names = columns.values_at(*index_keys).compact\n    case_sensitive = true\n\n    # extract column names from the expression, for a\n    # case-insensitive index.\n    # only applies to character, character varying, and text\n    if expression\n      rexp_lower = %r{\\blower\\(\\(?([^)]+)(\\)::text)?\\)}\n      if expression.match /\\A\#{rexp_lower}(?:, \#{rexp_lower})*\\z/i\n        case_insensitive_columns = expression.scan(rexp_lower).map(&:first).select{|column| %W[char varchar text].include? types[column]}\n        if case_insensitive_columns.any?\n          case_sensitive = false\n          column_names = index_keys.map { |index_key|\n            index_key == '0' ? case_insensitive_columns.shift : columns[index_key]\n          }.compact | column_names\n        end\n      end\n    end\n\n    get_opclass_names(env, opclasses)\n    operator_classes = Hash[\n      index_keys.zip(opclasses).map { |index_key, opclass| [columns[index_key], @opclass_names[opclass]] }\n    ]\n    operator_classes.delete_if{|k,v| v.nil?}\n\n    # add info on sort order for columns (only desc order is explicitly specified, asc is the default)\n    desc_order_columns = inddef.scan(/(\\w+) DESC/).flatten\n    orders = desc_order_columns.any? ? Hash[column_names.map {|column| [column, desc_order_columns.include?(column) ? :desc : :asc]}] : {}\n\n    ::ActiveRecord::ConnectionAdapters::IndexDefinition.new(env.table_name, column_names,\n                                                            :name => index_name,\n                                                            :unique => (unique == 't'),\n                                                            :orders => orders,\n                                                            :where => conditions,\n                                                            :case_sensitive => case_sensitive,\n                                                            :using => using.downcase == \"btree\" ? nil : using.to_sym,\n                                                            :operator_classes => operator_classes,\n                                                            :expression => expression)\n  end\nend\n", 'SCHEMA')

#namespace_sql(table_name) ⇒ Object 



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# File 'lib/schema_plus_pg_indexes/middleware/postgresql/schema.rb', line 112

def namespace_sql(table_name)
  (table_name.to_s =~ /(.*)[.]/) ?  "'#{$1}'" : "ANY (current_schemas(false))"
end

#table_name_without_namespace(table_name) ⇒ Object 



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# File 'lib/schema_plus_pg_indexes/middleware/postgresql/schema.rb', line 116

def table_name_without_namespace(table_name)
  table_name.to_s.sub /.*[.]/, ''
end