Module: SchemaPlus::ActiveRecord::ConnectionAdapters::PostgresqlAdapter

Defined in:
lib/schema_plus/active_record/connection_adapters/postgresql_adapter.rb

Overview

The Postgresql adapter implements the SchemaPlus extensions and enhancements

Defined Under Namespace

Modules: AddColumnOptions

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.included(base) ⇒ Object

:nodoc:



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

def self.included(base) #:nodoc:
  base.class_eval do
    if ::ActiveRecord::VERSION::MAJOR.to_i < 4 && !defined?(JRUBY_VERSION)
      remove_method :indexes
    end
    alias_method_chain :rename_table, :schema_plus
    alias_method_chain :exec_cache, :schema_plus unless defined?(JRUBY_VERSION)
  end
  ::ActiveRecord::ConnectionAdapters::PostgreSQLColumn.send(:include, PostgreSQLColumn) unless ::ActiveRecord::ConnectionAdapters::PostgreSQLColumn.include?(PostgreSQLColumn)
end

Instance Method Details

#add_index(table_name, column_name, options = {}) ⇒ Object

SchemaPlus provides the following extra options for Postgres indexes:

  • :conditions - SQL conditions for the WHERE clause of the index

  • :expression - SQL expression to index. column_name can be nil or ommitted, in which case :name must be provided

  • :kind - index method for Postgresql to use

  • +:case_sensitive - setting to false is a shorthand for :expression => ‘LOWER(column_name)’

The :case_sensitive => false option ties in with Rails built-in support for case-insensitive searching:

validates_uniqueness_of :name, :case_sensitive => false

Since since :case_sensitive => false is implemented by using :expression, this raises an ArgumentError if both are specified simultaneously.



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# File 'lib/schema_plus/active_record/connection_adapters/postgresql_adapter.rb', line 85

def add_index(table_name, column_name, options = {})
  column_name, options = [], column_name if column_name.is_a?(Hash)
  column_names = Array(column_name).compact
  if column_names.empty?
    raise ArgumentError, "No columns and :expression missing from options - cannot create index" unless options[:expression]
    raise ArgumentError, "Index name not given. Pass :name option" unless options[:name]
  end

  index_type = options[:unique] ? "UNIQUE" : ""
  index_name = options[:name] || index_name(table_name, column_names)
  conditions = options[:conditions]
  kind       = options[:kind]

  if expression = options[:expression] then
    raise ArgumentError, "Cannot specify :case_sensitive => false with an expression.  Use LOWER(column_name)" if options[:case_sensitive] == false
    # Wrap expression in parentheses if necessary
    expression = "(#{expression})" if expression !~ /(using|with|tablespace|where)/i
    expression = "USING #{kind} #{expression}" if kind
    expression = "#{expression} WHERE #{conditions}" if conditions

    sql = "CREATE #{index_type} INDEX #{quote_column_name(index_name)} ON #{quote_table_name(table_name)} #{expression}"
  else
    option_strings = Hash[column_names.map {|name| [name, '']}]
    option_strings = add_index_sort_order(option_strings, column_names, options)

    if options[:case_sensitive] == false
      caseable_columns = columns(table_name).select { |col| [:string, :text].include?(col.type) }.map(&:name)
      quoted_column_names = column_names.map do |col_name|
        (caseable_columns.include?(col_name.to_s) ? "LOWER(#{quote_column_name(col_name)})" : quote_column_name(col_name)) + option_strings[col_name]
      end
    else
      quoted_column_names = column_names.map { |col_name| quote_column_name(col_name) + option_strings[col_name] }
    end

    expression = "(#{quoted_column_names.join(', ')})"
    expression = "USING #{kind} #{expression}" if kind

    sql = "CREATE #{index_type} INDEX #{quote_column_name(index_name)} ON #{quote_table_name(table_name)} #{expression}"
    sql += " WHERE (#{ ::ActiveRecord::Base.send(:sanitize_sql, conditions, quote_table_name(table_name)) })" if conditions
  end
  execute sql
rescue => e
  SchemaStatements.add_index_exception_handler(self, table_name, column_names, options, e)
end

#exec_cache_with_schema_plus(sql, *args) ⇒ Object

Prepass to replace each ActiveRecord::DB_DEFAULT with a literal DEFAULT in the sql string. (The underlying pg gem provides no way to bind a value that will replace $n with DEFAULT)



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# File 'lib/schema_plus/active_record/connection_adapters/postgresql_adapter.rb', line 218

def exec_cache_with_schema_plus(sql, *args)
  name_passed = (2 == args.size)
  binds, name = args.reverse

  if binds.any?{ |col, val| val.equal? ::ActiveRecord::DB_DEFAULT}
    j = 0
    binds.each_with_index do |(col, val), i|
    if val.equal? ::ActiveRecord::DB_DEFAULT
      sql = sql.sub(/\$#{i+1}/, 'DEFAULT')
    else
      sql = sql.sub(/\$#{i+1}/, "$#{j+1}") if i != j
      j += 1
    end
    end
    binds = binds.reject{|col, val| val.equal? ::ActiveRecord::DB_DEFAULT}
  end

  args = name_passed ? [name, binds] : [binds]
  exec_cache_without_schema_plus(sql, *args)
end

#foreign_keys(table_name, name = nil) ⇒ Object

:nodoc:



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# File 'lib/schema_plus/active_record/connection_adapters/postgresql_adapter.rb', line 239

def foreign_keys(table_name, name = nil) #:nodoc:
  load_foreign_keys(<<-SQL, name)
SELECT f.conname, pg_get_constraintdef(f.oid), t.relname
  FROM pg_class t, pg_constraint f
 WHERE f.conrelid = t.oid
   AND f.contype = 'f'
   AND t.relname = '#{table_name_without_namespace(table_name)}'
   AND t.relnamespace IN (SELECT oid FROM pg_namespace WHERE nspname = #{namespace_sql(table_name)} )
  SQL
end

#indexes(table_name, name = nil) ⇒ Object

This method entirely duplicated from AR’s postgresql_adapter.c, but includes the extra bit to determine the column name for a case-insensitive index. (Haven’t come up with any clever way to only code up the case-insensitive column name bit here and otherwise use the existing method.)



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# File 'lib/schema_plus/active_record/connection_adapters/postgresql_adapter.rb', line 139

def indexes(table_name, name = nil) #:nodoc:
  result = query(<<-SQL, name)

   SELECT distinct i.relname, d.indisunique, d.indkey, pg_get_indexdef(d.indexrelid), t.oid,
          m.amname, pg_get_expr(d.indpred, t.oid) as conditions, pg_get_expr(d.indexprs, t.oid) as expression
   FROM pg_class t
   INNER JOIN pg_index d ON t.oid = d.indrelid
   INNER JOIN pg_class i ON d.indexrelid = i.oid
   INNER JOIN pg_am m ON i.relam = m.oid
   WHERE i.relkind = 'i'
     AND d.indisprimary = 'f'
     AND t.relname = '#{table_name_without_namespace(table_name)}'
     AND i.relnamespace IN (SELECT oid FROM pg_namespace WHERE nspname = #{namespace_sql(table_name)} )
  ORDER BY i.relname
  SQL

  result.map do |(index_name, is_unique, indkey, inddef, oid, kind, conditions, expression)|
    unique = (is_unique == 't')
    index_keys = indkey.split(" ")

    rows = query(<<-SQL, "Columns for index #{index_name} on #{table_name}")
      SELECT CAST(a.attnum as VARCHAR), a.attname, t.typname
      FROM pg_attribute a
      INNER JOIN pg_type t ON a.atttypid = t.oid
      WHERE a.attrelid = #{oid}
    SQL
    columns = {}
    types = {}
    rows.each do |num, name, type|
      columns[num] = name
      types[name] = type
    end

    column_names = columns.values_at(*index_keys).compact
    case_sensitive = true

    # extract column names from the expression, for a
    # case-insensitive index.
    # only applies to character, character varying, and text
    if expression
      rexp_lower = %r{\blower\(\(?([^)]+)(\)::text)?\)}
      if expression.match /\A#{rexp_lower}(?:, #{rexp_lower})*\z/
        case_insensitive_columns = expression.scan(rexp_lower).map(&:first).select{|column| %W[char varchar text].include? types[column]}
        if case_insensitive_columns.any?
          case_sensitive = false
          column_names = index_keys.map { |index_key|
            index_key == '0' ? case_insensitive_columns.shift : columns[index_key]
          }.compact
        end
      end
    end

    # add info on sort order for columns (only desc order is explicitly specified, asc is the default)
    desc_order_columns = inddef.scan(/(\w+) DESC/).flatten
    orders = desc_order_columns.any? ? Hash[column_names.map {|column| [column, desc_order_columns.include?(column) ? :desc : :asc]}] : {}

    ::ActiveRecord::ConnectionAdapters::IndexDefinition.new(table_name, column_names,
                                                            :name => index_name,
                                                            :unique => unique,
                                                            :orders => orders,
                                                            :conditions => conditions,
                                                            :case_sensitive => case_sensitive,
                                                            :kind => kind.downcase == "btree" ? nil : kind,
                                                            :expression => expression)
  end
end

#query(*args) ⇒ Object 



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# File 'lib/schema_plus/active_record/connection_adapters/postgresql_adapter.rb', line 206

def query(*args)
  select(*args).map(&:values)
end

#rename_table_with_schema_plus(oldname, newname) ⇒ Object

:nodoc:



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# File 'lib/schema_plus/active_record/connection_adapters/postgresql_adapter.rb', line 210

def rename_table_with_schema_plus(oldname, newname) #:nodoc:
  rename_table_without_schema_plus(oldname, newname)
  rename_indexes_and_foreign_keys(oldname, newname)
end

#reverse_foreign_keys(table_name, name = nil) ⇒ Object

:nodoc:



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# File 'lib/schema_plus/active_record/connection_adapters/postgresql_adapter.rb', line 250

def reverse_foreign_keys(table_name, name = nil) #:nodoc:
  load_foreign_keys(<<-SQL, name)
SELECT f.conname, pg_get_constraintdef(f.oid), t2.relname
  FROM pg_class t, pg_class t2, pg_constraint f
 WHERE f.confrelid = t.oid
   AND f.conrelid = t2.oid
   AND f.contype = 'f'
   AND t.relname = '#{table_name_without_namespace(table_name)}'
   AND t.relnamespace IN (SELECT oid FROM pg_namespace WHERE nspname = #{namespace_sql(table_name)} )
  SQL
end

#supports_partial_indexes? ⇒ Boolean

:nodoc:

Returns:

  • (Boolean) 


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# File 'lib/schema_plus/active_record/connection_adapters/postgresql_adapter.rb', line 130

def supports_partial_indexes? #:nodoc:
  true
end

#view_definition(view_name, name = nil) ⇒ Object

:nodoc:



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# File 'lib/schema_plus/active_record/connection_adapters/postgresql_adapter.rb', line 272

def view_definition(view_name, name = nil) #:nodoc:
  result = query(<<-SQL, name)
SELECT pg_get_viewdef(oid)
  FROM pg_class
 WHERE relkind = 'v'
   AND relname = '#{view_name}'
  SQL
  row = result.first
  row.first.chomp(';') unless row.nil?
end

#views(name = nil) ⇒ Object

:nodoc:



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# File 'lib/schema_plus/active_record/connection_adapters/postgresql_adapter.rb', line 262

def views(name = nil) #:nodoc:
  sql = <<-SQL
    SELECT viewname
      FROM pg_views
    WHERE schemaname = ANY (current_schemas(false))
  SQL
  sql += " AND schemaname != 'postgis'" if adapter_name == 'PostGIS'
  query(sql, name).map { |row| row[0] }
end