module ActiveRecord::ConnectionAdapters::PostgreSQL::SchemaStatements

Public Instance Methods

change_column(table_name, column_name, type, options = {}) click to toggle source

Changes the column of a table.

# File lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 427
def change_column(table_name, column_name, type, options = {})
  clear_cache!
  quoted_table_name = quote_table_name(table_name)
  sql_type = type_to_sql(type, options[:limit], options[:precision], options[:scale])
  sql_type << "[]" if options[:array]
  sql = "ALTER TABLE #{quoted_table_name} ALTER COLUMN #{quote_column_name(column_name)} TYPE #{sql_type}"
  sql << " USING #{options[:using]}" if options[:using]
  if options[:cast_as]
    sql << " USING CAST(#{quote_column_name(column_name)} AS #{type_to_sql(options[:cast_as], options[:limit], options[:precision], options[:scale])})"
  end
  execute sql

  change_column_default(table_name, column_name, options[:default]) if options_include_default?(options)
  change_column_null(table_name, column_name, options[:null], options[:default]) if options.key?(:null)
end
change_column_default(table_name, column_name, default) click to toggle source

Changes the default value of a table column.

# File lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 444
def change_column_default(table_name, column_name, default)
  clear_cache!
  column = column_for(table_name, column_name)
  return unless column

  alter_column_query = "ALTER TABLE #{quote_table_name(table_name)} ALTER COLUMN #{quote_column_name(column_name)} %s"
  if default.nil?
    # <tt>DEFAULT NULL</tt> results in the same behavior as <tt>DROP DEFAULT</tt>. However, PostgreSQL will
    # cast the default to the columns type, which leaves us with a default like "default NULL::character varying".
    execute alter_column_query % "DROP DEFAULT"
  else
    execute alter_column_query % "SET DEFAULT #{quote_default_value(default, column)}"
  end
end
change_column_null(table_name, column_name, null, default = nil) click to toggle source
# File lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 459
def change_column_null(table_name, column_name, null, default = nil)
  clear_cache!
  unless null || default.nil?
    column = column_for(table_name, column_name)
    execute("UPDATE #{quote_table_name(table_name)} SET #{quote_column_name(column_name)}=#{quote_default_value(default, column)} WHERE #{quote_column_name(column_name)} IS NULL") if column
  end
  execute("ALTER TABLE #{quote_table_name(table_name)} ALTER #{quote_column_name(column_name)} #{null ? 'DROP' : 'SET'} NOT NULL")
end
client_min_messages() click to toggle source

Returns the current client message level.

# File lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 269
def client_min_messages
  query('SHOW client_min_messages', 'SCHEMA')[0][0]
end
client_min_messages=(level) click to toggle source

Set the client message level.

# File lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 274
def client_min_messages=(level)
  execute("SET client_min_messages TO '#{level}'", 'SCHEMA')
end
collation() click to toggle source

Returns the current database collation.

# File lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 217
        def collation
          query("            SELECT pg_database.datcollate FROM pg_database WHERE pg_database.datname LIKE '#{current_database}'
", 'SCHEMA')[0][0]
        end
columns(table_name) click to toggle source

Returns the list of all column definitions for a table.

# File lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 184
def columns(table_name)
  # Limit, precision, and scale are all handled by the superclass.
  column_definitions(table_name).map do |column_name, type, default, notnull, oid, fmod|
    oid = get_oid_type(oid.to_i, fmod.to_i, column_name, type)
    default_value = extract_value_from_default(oid, default)
    default_function = extract_default_function(default_value, default)
    new_column(column_name, default_value, oid, type, notnull == 'f', default_function)
  end
end
create_database(name, options = {}) click to toggle source

Create a new PostgreSQL database. Options include :owner, :template, :encoding (defaults to utf8), :collation, :ctype, :tablespace, and :connection_limit (note that MySQL uses :charset while PostgreSQL uses :encoding).

Example:

create_database config[:database], config
create_database 'foo_development', encoding: 'unicode'
# File lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 54
def create_database(name, options = {})
  options = { encoding: 'utf8' }.merge!(options.symbolize_keys)

  option_string = options.inject("") do |memo, (key, value)|
    memo += case key
    when :owner
      " OWNER = \"#{value}\""
    when :template
      " TEMPLATE = \"#{value}\""
    when :encoding
      " ENCODING = '#{value}'"
    when :collation
      " LC_COLLATE = '#{value}'"
    when :ctype
      " LC_CTYPE = '#{value}'"
    when :tablespace
      " TABLESPACE = \"#{value}\""
    when :connection_limit
      " CONNECTION LIMIT = #{value}"
    else
      ""
    end
  end

  execute "CREATE DATABASE #{quote_table_name(name)}#{option_string}"
end
create_schema(schema_name) click to toggle source

Creates a schema for the given schema name.

# File lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 242
def create_schema schema_name
  execute "CREATE SCHEMA #{schema_name}"
end
ctype() click to toggle source

Returns the current database ctype.

# File lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 224
        def ctype
          query("            SELECT pg_database.datctype FROM pg_database WHERE pg_database.datname LIKE '#{current_database}'
", 'SCHEMA')[0][0]
        end
current_database() click to toggle source

Returns the current database name.

# File lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 199
def current_database
  query('select current_database()', 'SCHEMA')[0][0]
end
current_schema() click to toggle source

Returns the current schema name.

# File lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 204
def current_schema
  query('SELECT current_schema', 'SCHEMA')[0][0]
end
drop_schema(schema_name) click to toggle source

Drops the schema for the given schema name.

# File lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 247
def drop_schema schema_name
  execute "DROP SCHEMA #{schema_name} CASCADE"
end
drop_table(table_name, options = {}) click to toggle source
# File lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 115
def drop_table(table_name, options = {})
  execute "DROP TABLE #{quote_table_name(table_name)}#{' CASCADE' if options[:force] == :cascade}"
end
encoding() click to toggle source

Returns the current database encoding format.

# File lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 209
        def encoding
          query("            SELECT pg_encoding_to_char(pg_database.encoding) FROM pg_database
            WHERE pg_database.datname LIKE '#{current_database}'
", 'SCHEMA')[0][0]
        end
foreign_keys(table_name) click to toggle source
# File lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 490
        def foreign_keys(table_name)
          fk_info = select_all "            SELECT t2.oid::regclass::text AS to_table, a1.attname AS column, a2.attname AS primary_key, c.conname AS name, c.confupdtype AS on_update, c.confdeltype AS on_delete
            FROM pg_constraint c
            JOIN pg_class t1 ON c.conrelid = t1.oid
            JOIN pg_class t2 ON c.confrelid = t2.oid
            JOIN pg_attribute a1 ON a1.attnum = c.conkey[1] AND a1.attrelid = t1.oid
            JOIN pg_attribute a2 ON a2.attnum = c.confkey[1] AND a2.attrelid = t2.oid
            JOIN pg_namespace t3 ON c.connamespace = t3.oid
            WHERE c.contype = 'f'
              AND t1.relname = #{quote(table_name)}
              AND t3.nspname = ANY (current_schemas(false))
            ORDER BY c.conname
".strip_heredoc

          fk_info.map do |row|
            options = {
              column: row['column'],
              name: row['name'],
              primary_key: row['primary_key']
            }

            options[:on_delete] = extract_foreign_key_action(row['on_delete'])
            options[:on_update] = extract_foreign_key_action(row['on_update'])

            ForeignKeyDefinition.new(table_name, row['to_table'], options)
          end
        end
index_name_exists?(table_name, index_name, default) click to toggle source
# File lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 128
        def index_name_exists?(table_name, index_name, default)
          exec_query("            SELECT COUNT(*)
            FROM pg_class t
            INNER JOIN pg_index d ON t.oid = d.indrelid
            INNER JOIN pg_class i ON d.indexrelid = i.oid
            WHERE i.relkind = 'i'
              AND i.relname = '#{index_name}'
              AND t.relname = '#{table_name}'
              AND i.relnamespace IN (SELECT oid FROM pg_namespace WHERE nspname = ANY (current_schemas(false)) )
", 'SCHEMA').rows.first[0].to_i > 0
        end
index_name_length() click to toggle source
# File lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 527
def index_name_length
  63
end
indexes(table_name, name = nil) click to toggle source

Returns an array of indexes for the given table.

# File lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 142
        def indexes(table_name, name = nil)
           result = query("             SELECT distinct i.relname, d.indisunique, d.indkey, pg_get_indexdef(d.indexrelid), t.oid
             FROM pg_class t
             INNER JOIN pg_index d ON t.oid = d.indrelid
             INNER JOIN pg_class i ON d.indexrelid = i.oid
             WHERE i.relkind = 'i'
               AND d.indisprimary = 'f'
               AND t.relname = '#{table_name}'
               AND i.relnamespace IN (SELECT oid FROM pg_namespace WHERE nspname = ANY (current_schemas(false)) )
            ORDER BY i.relname
", 'SCHEMA')

          result.map do |row|
            index_name = row[0]
            unique = row[1] == 't'
            indkey = row[2].split(" ")
            inddef = row[3]
            oid = row[4]

            columns = Hash[query("            SELECT a.attnum, a.attname
            FROM pg_attribute a
            WHERE a.attrelid = #{oid}
            AND a.attnum IN (#{indkey.join(",")})
", "SCHEMA")]

            column_names = columns.values_at(*indkey).compact

            unless column_names.empty?
              # 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[desc_order_columns.map {|order_column| [order_column, :desc]}] : {}
              where = inddef.scan(/WHERE (.+)$/).flatten[0]
              using = inddef.scan(/USING (.+?) /).flatten[0].to_sym

              IndexDefinition.new(table_name, index_name, unique, column_names, [], orders, where, nil, using)
            end
          end.compact
        end
primary_key(table) click to toggle source

Returns just a table's primary key

# File lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 388
        def primary_key(table)
          pks = exec_query("            SELECT attr.attname
            FROM pg_attribute attr
            INNER JOIN pg_constraint cons ON attr.attrelid = cons.conrelid AND attr.attnum = any(cons.conkey)
            WHERE cons.contype = 'p'
              AND cons.conrelid = '#{quote_table_name(table)}'::regclass
", 'SCHEMA').rows
          return nil unless pks.count == 1
          pks[0][0]
        end
rename_index(table_name, old_name, new_name) click to toggle source
# File lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 484
def rename_index(table_name, old_name, new_name)
  validate_index_length!(table_name, new_name)

  execute "ALTER INDEX #{quote_column_name(old_name)} RENAME TO #{quote_table_name(new_name)}"
end
rename_table(table_name, new_name) click to toggle source

Renames a table. Also renames a table's primary key sequence if the sequence name exists and matches the Active Record default.

Example:

rename_table('octopuses', 'octopi')
# File lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 406
def rename_table(table_name, new_name)
  clear_cache!
  execute "ALTER TABLE #{quote_table_name(table_name)} RENAME TO #{quote_table_name(new_name)}"
  pk, seq = pk_and_sequence_for(new_name)
  if seq && seq.identifier == "#{table_name}_#{pk}_seq"
    new_seq = "#{new_name}_#{pk}_seq"
    idx = "#{table_name}_pkey"
    new_idx = "#{new_name}_pkey"
    execute "ALTER TABLE #{quote_table_name(seq)} RENAME TO #{quote_table_name(new_seq)}"
    execute "ALTER INDEX #{quote_table_name(idx)} RENAME TO #{quote_table_name(new_idx)}"
  end

  rename_table_indexes(table_name, new_name)
end
schema_exists?(name) click to toggle source

Returns true if schema exists.

# File lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 120
        def schema_exists?(name)
          exec_query("            SELECT COUNT(*)
            FROM pg_namespace
            WHERE nspname = '#{name}'
", 'SCHEMA').rows.first[0].to_i > 0
        end
schema_names() click to toggle source

Returns an array of schema names.

# File lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 231
        def schema_names
          query("            SELECT nspname
              FROM pg_namespace
             WHERE nspname !~ '^pg_.*'
               AND nspname NOT IN ('information_schema')
             ORDER by nspname;
", 'SCHEMA').flatten
        end
schema_search_path() click to toggle source

Returns the active schema search path.

# File lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 264
def schema_search_path
  @schema_search_path ||= query('SHOW search_path', 'SCHEMA')[0][0]
end
schema_search_path=(schema_csv) click to toggle source

Sets the schema search path to a string of comma-separated schema names. Names beginning with $ have to be quoted (e.g. $user => '$user'). See: www.postgresql.org/docs/current/static/ddl-schemas.html

This should be not be called manually but set in database.yml.

# File lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 256
def schema_search_path=(schema_csv)
  if schema_csv
    execute("SET search_path TO #{schema_csv}", 'SCHEMA')
    @schema_search_path = schema_csv
  end
end
serial_sequence(table, column) click to toggle source
# File lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 287
        def serial_sequence(table, column)
          result = exec_query("            SELECT pg_get_serial_sequence('#{table}', '#{column}')
", 'SCHEMA')
          result.rows.first.first
        end
table_exists?(name) click to toggle source

Returns true if table exists. If the schema is not specified as part of name then it will only find tables within the current schema search path (regardless of permissions to access tables in other schemas)

# File lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 101
        def table_exists?(name)
          name = Utils.extract_schema_qualified_name(name.to_s)
          return false unless name.identifier

          exec_query("              SELECT COUNT(*)
              FROM pg_class c
              LEFT JOIN pg_namespace n ON n.oid = c.relnamespace
              WHERE c.relkind IN ('r','v','m') -- (r)elation/table, (v)iew, (m)aterialized view
              AND c.relname = '#{name.identifier}'
              AND n.nspname = #{name.schema ? "'#{name.schema}'" : 'ANY (current_schemas(false))'}
", 'SCHEMA').rows.first[0].to_i > 0
        end
tables(name = nil) click to toggle source

Returns the list of all tables in the schema search path.

# File lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 90
        def tables(name = nil)
          query("            SELECT tablename
            FROM pg_tables
            WHERE schemaname = ANY (current_schemas(false))
", 'SCHEMA').map { |row| row[0] }
        end
type_to_sql(type, limit = nil, precision = nil, scale = nil) click to toggle source

Maps logical Rails types to PostgreSQL-specific data types.

Calls superclass method
# File lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 532
def type_to_sql(type, limit = nil, precision = nil, scale = nil)
  case type.to_s
  when 'binary'
    # PostgreSQL doesn't support limits on binary (bytea) columns.
    # The hard limit is 1Gb, because of a 32-bit size field, and TOAST.
    case limit
    when nil, 0..0x3fffffff; super(type)
    else raise(ActiveRecordError, "No binary type has byte size #{limit}.")
    end
  when 'text'
    # PostgreSQL doesn't support limits on text columns.
    # The hard limit is 1Gb, according to section 8.3 in the manual.
    case limit
    when nil, 0..0x3fffffff; super(type)
    else raise(ActiveRecordError, "The limit on text can be at most 1GB - 1byte.")
    end
  when 'integer'
    return 'integer' unless limit

    case limit
      when 1, 2; 'smallint'
      when 3, 4; 'integer'
      when 5..8; 'bigint'
      else raise(ActiveRecordError, "No integer type has byte size #{limit}. Use a numeric with precision 0 instead.")
    end
  when 'datetime'
    return super unless precision

    case precision
      when 0..6; "timestamp(#{precision})"
      else raise(ActiveRecordError, "No timestamp type has precision of #{precision}. The allowed range of precision is from 0 to 6")
    end
  else
    super
  end
end