Module: ActiveRecord::ConnectionAdapters::PostgreSQL::SchemaStatements

Included in:
ActiveRecord::ConnectionAdapters::PostgreSQLAdapter
Defined in:
lib/active_record/connection_adapters/postgresql/schema_statements.rb

Instance Method Summary collapse

Instance Method Details

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

Adds a new column to the named table. See TableDefinition#column for details of the options you can use.



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 423

def add_column(table_name, column_name, type, options = {})
  clear_cache!
  super
end

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

:nodoc:



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 477

def add_index(table_name, column_name, options = {}) #:nodoc:
  index_name, index_type, index_columns, index_options, index_algorithm, index_using = add_index_options(table_name, column_name, options)
  execute "CREATE #{index_type} INDEX #{index_algorithm} #{quote_column_name(index_name)} ON #{quote_table_name(table_name)} #{index_using} (#{index_columns})#{index_options}"
end

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

Changes the column of a table.



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 429

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) ⇒ Object

Changes the default value of a table column.



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 446

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) ⇒ Object 



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 461

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 ⇒ Object

Returns the current client message level.



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# 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) ⇒ Object

Set the client message level.



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# 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 ⇒ Object

Returns the current database collation.



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# 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}'\n  end_sql\nend\n", 'SCHEMA')[0][0]

#columns(table_name) ⇒ Object

Returns the list of all column definitions for a table.



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# 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

#columns_for_distinct(columns, orders) ⇒ Object

PostgreSQL requires the ORDER BY columns in the select list for distinct queries, and requires that the ORDER BY include the distinct column.



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 573

def columns_for_distinct(columns, orders) #:nodoc:
  order_columns = orders.reject(&:blank?).map{ |s|
      # Convert Arel node to string
      s = s.to_sql unless s.is_a?(String)
      # Remove any ASC/DESC modifiers
      s.gsub(/\s+(?:ASC|DESC)\b/i, '')
       .gsub(/\s+NULLS\s+(?:FIRST|LAST)\b/i, '')
    }.reject(&:blank?).map.with_index { |column, i| "#{column} AS alias_#{i}" }

  [super, *order_columns].join(', ')
end

#create_database(name, options = {}) ⇒ Object

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'



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# 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) ⇒ Object

Creates a schema for the given schema name.



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 242

def create_schema schema_name
  execute "CREATE SCHEMA #{schema_name}"
end

#ctype ⇒ Object

Returns the current database ctype.



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# 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}'\n  end_sql\nend\n", 'SCHEMA')[0][0]

#current_database ⇒ Object

Returns the current database name.



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# 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 ⇒ Object

Returns the current schema name.



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 204

def current_schema
  query('SELECT current_schema', 'SCHEMA')[0][0]
end

#default_sequence_name(table_name, pk = nil) ⇒ Object

Returns the sequence name for a table’s primary key or some other specified key.



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 279

def default_sequence_name(table_name, pk = nil) #:nodoc:
  result = serial_sequence(table_name, pk || 'id')
  return nil unless result
  Utils.extract_schema_qualified_name(result).to_s
rescue ActiveRecord::StatementInvalid
  PostgreSQL::Name.new(nil, "#{table_name}_#{pk || 'id'}_seq").to_s
end

#drop_database(name) ⇒ Object

Drops a PostgreSQL database.

Example:

drop_database 'matt_development'



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 85

def drop_database(name) #:nodoc:
  execute "DROP DATABASE IF EXISTS #{quote_table_name(name)}"
end

#drop_schema(schema_name) ⇒ Object

Drops the schema for the given schema name.



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# 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 = {}) ⇒ Object 



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# 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 ⇒ Object

Returns the current database encoding format.



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# 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\n    WHERE pg_database.datname LIKE '\#{current_database}'\n  end_sql\nend\n", 'SCHEMA')[0][0]

#extract_foreign_key_action(specifier) ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 521

def extract_foreign_key_action(specifier) # :nodoc:
  case specifier
  when 'c'; :cascade
  when 'n'; :nullify
  when 'r'; :restrict
  end
end

#foreign_keys(table_name) ⇒ Object 



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 492

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\n    FROM pg_constraint c\n    JOIN pg_class t1 ON c.conrelid = t1.oid\n    JOIN pg_class t2 ON c.confrelid = t2.oid\n    JOIN pg_attribute a1 ON a1.attnum = c.conkey[1] AND a1.attrelid = t1.oid\n    JOIN pg_attribute a2 ON a2.attnum = c.confkey[1] AND a2.attrelid = t2.oid\n    JOIN pg_namespace t3 ON c.connamespace = t3.oid\n    WHERE c.contype = 'f'\n      AND t1.relname = \#{quote(table_name)}\n      AND t3.nspname = ANY (current_schemas(false))\n    ORDER BY c.conname\n  SQL\n\n  fk_info.map do |row|\n    options = {\n      column: row['column'],\n      name: row['name'],\n      primary_key: row['primary_key']\n    }\n\n    options[:on_delete] = extract_foreign_key_action(row['on_delete'])\n    options[:on_update] = extract_foreign_key_action(row['on_update'])\n\n    ForeignKeyDefinition.new(table_name, row['to_table'], options)\n  end\nend\n".strip_heredoc

#index_name_exists?(table_name, index_name, default) ⇒ Boolean

Returns:

  • (Boolean) 


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# 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(*)\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    WHERE i.relkind = 'i'\n      AND i.relname = '\#{index_name}'\n      AND t.relname = '\#{table_name}'\n      AND i.relnamespace IN (SELECT oid FROM pg_namespace WHERE nspname = ANY (current_schemas(false)) )\n  SQL\nend\n", 'SCHEMA').rows.first[0].to_i > 0

#index_name_length ⇒ Object 



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 529

def index_name_length
  63
end

#indexes(table_name, name = nil) ⇒ Object

Returns an array of indexes for the given table.



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# 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\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     WHERE i.relkind = 'i'\n       AND d.indisprimary = 'f'\n       AND t.relname = '\#{table_name}'\n       AND i.relnamespace IN (SELECT oid FROM pg_namespace WHERE nspname = ANY (current_schemas(false)) )\n    ORDER BY i.relname\n  SQL\n\n  result.map do |row|\n    index_name = row[0]\n    unique = row[1] == 't'\n    indkey = row[2].split(\" \")\n    inddef = row[3]\n    oid = row[4]\n\n    columns = Hash[query(<<-SQL, \"SCHEMA\")]\n    SELECT a.attnum, a.attname\n    FROM pg_attribute a\n    WHERE a.attrelid = \#{oid}\n    AND a.attnum IN (\#{indkey.join(\",\")})\n    SQL\n\n    column_names = columns.values_at(*indkey).compact\n\n    unless column_names.empty?\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[desc_order_columns.map {|order_column| [order_column, :desc]}] : {}\n      where = inddef.scan(/WHERE (.+)$/).flatten[0]\n      using = inddef.scan(/USING (.+?) /).flatten[0].to_sym\n\n      IndexDefinition.new(table_name, index_name, unique, column_names, [], orders, where, nil, using)\n    end\n  end.compact\nend\n", 'SCHEMA')

#new_column(name, default, cast_type, sql_type = nil, null = true, default_function = nil) ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 194

def new_column(name, default, cast_type, sql_type = nil, null = true, default_function = nil) # :nodoc:
  PostgreSQLColumn.new(name, default, cast_type, sql_type, null, default_function)
end

#pk_and_sequence_for(table) ⇒ Object

Returns a table’s primary key and belonging sequence.



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 334

def pk_and_sequence_for(table) #:nodoc:
  # First try looking for a sequence with a dependency on the
  # given table's primary key.
  result = query("    SELECT attr.attname, nsp.nspname, seq.relname\n    FROM pg_class      seq,\n         pg_attribute  attr,\n         pg_depend     dep,\n         pg_constraint cons,\n         pg_namespace  nsp\n    WHERE seq.oid           = dep.objid\n      AND seq.relkind       = 'S'\n      AND attr.attrelid     = dep.refobjid\n      AND attr.attnum       = dep.refobjsubid\n      AND attr.attrelid     = cons.conrelid\n      AND attr.attnum       = cons.conkey[1]\n      AND seq.relnamespace  = nsp.oid\n      AND cons.contype      = 'p'\n      AND dep.classid       = 'pg_class'::regclass\n      AND dep.refobjid      = '\#{quote_table_name(table)}'::regclass\n  end_sql\n\n  if result.nil? or result.empty?\n    result = query(<<-end_sql, 'SCHEMA')[0]\n      SELECT attr.attname, nsp.nspname,\n        CASE\n          WHEN pg_get_expr(def.adbin, def.adrelid) !~* 'nextval' THEN NULL\n          WHEN split_part(pg_get_expr(def.adbin, def.adrelid), '''', 2) ~ '.' THEN\n            substr(split_part(pg_get_expr(def.adbin, def.adrelid), '''', 2),\n                   strpos(split_part(pg_get_expr(def.adbin, def.adrelid), '''', 2), '.')+1)\n          ELSE split_part(pg_get_expr(def.adbin, def.adrelid), '''', 2)\n        END\n      FROM pg_class       t\n      JOIN pg_attribute   attr ON (t.oid = attrelid)\n      JOIN pg_attrdef     def  ON (adrelid = attrelid AND adnum = attnum)\n      JOIN pg_constraint  cons ON (conrelid = adrelid AND adnum = conkey[1])\n      JOIN pg_namespace   nsp  ON (t.relnamespace = nsp.oid)\n      WHERE t.oid = '\#{quote_table_name(table)}'::regclass\n        AND cons.contype = 'p'\n        AND pg_get_expr(def.adbin, def.adrelid) ~* 'nextval|uuid_generate'\n    end_sql\n  end\n\n  pk = result.shift\n  if result.last\n    [pk, PostgreSQL::Name.new(*result)]\n  else\n    [pk, nil]\n  end\nrescue\n  nil\nend\n", 'SCHEMA')[0]

#primary_key(table) ⇒ Object

Returns just a table’s primary key



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 388

def primary_key(table)
  pks = exec_query("    SELECT attr.attname\n    FROM pg_attribute attr\n    INNER JOIN pg_constraint cons ON attr.attrelid = cons.conrelid AND attr.attnum = any(cons.conkey)\n    WHERE cons.contype = 'p'\n      AND cons.conrelid = '\#{quote_table_name(table)}'::regclass\n  end_sql\n  return nil unless pks.count == 1\n  pks[0][0]\nend\n", 'SCHEMA').rows

#recreate_database(name, options = {}) ⇒ Object

Drops the database specified on the name attribute and creates it again using the provided options.



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 41

def recreate_database(name, options = {}) #:nodoc:
  drop_database(name)
  create_database(name, options)
end

#remove_index!(table_name, index_name) ⇒ Object

:nodoc:



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 482

def remove_index!(table_name, index_name) #:nodoc:
  execute "DROP INDEX #{quote_table_name(index_name)}"
end

#rename_column(table_name, column_name, new_column_name) ⇒ Object

Renames a column in a table.



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 471

def rename_column(table_name, column_name, new_column_name)
  clear_cache!
  execute "ALTER TABLE #{quote_table_name(table_name)} RENAME COLUMN #{quote_column_name(column_name)} TO #{quote_column_name(new_column_name)}"
  rename_column_indexes(table_name, column_name, new_column_name)
end

#rename_index(table_name, old_name, new_name) ⇒ Object 



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 486

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) ⇒ Object

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')



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# 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

#reset_pk_sequence!(table, pk = nil, sequence = nil) ⇒ Object

Resets the sequence of a table’s primary key to the maximum value.



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 312

def reset_pk_sequence!(table, pk = nil, sequence = nil) #:nodoc:
  unless pk and sequence
    default_pk, default_sequence = pk_and_sequence_for(table)

    pk ||= default_pk
    sequence ||= default_sequence
  end

  if @logger && pk && !sequence
    @logger.warn "#{table} has primary key #{pk} with no default sequence"
  end

  if pk && sequence
    quoted_sequence = quote_table_name(sequence)

    select_value "      SELECT setval('\#{quoted_sequence}', (SELECT COALESCE(MAX(\#{quote_column_name pk})+(SELECT increment_by FROM \#{quoted_sequence}), (SELECT min_value FROM \#{quoted_sequence})) FROM \#{quote_table_name(table)}), false)\n    end_sql\n  end\nend\n", 'SCHEMA'

#schema_exists?(name) ⇒ Boolean

Returns true if schema exists.

Returns:

  • (Boolean) 


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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 120

def schema_exists?(name)
  exec_query("    SELECT COUNT(*)\n    FROM pg_namespace\n    WHERE nspname = '\#{name}'\n  SQL\nend\n", 'SCHEMA').rows.first[0].to_i > 0

#schema_names ⇒ Object

Returns an array of schema names.



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 231

def schema_names
  query("    SELECT nspname\n      FROM pg_namespace\n     WHERE nspname !~ '^pg_.*'\n       AND nspname NOT IN ('information_schema')\n     ORDER by nspname;\n  SQL\nend\n", 'SCHEMA').flatten

#schema_search_path ⇒ Object

Returns the active schema search path.



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# 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) ⇒ Object

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.



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# 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) ⇒ Object 



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# 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}')\n  eosql\n  result.rows.first.first\nend\n", 'SCHEMA')

#set_pk_sequence!(table, value) ⇒ Object

Sets the sequence of a table’s primary key to the specified value.



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 295

def set_pk_sequence!(table, value) #:nodoc:
  pk, sequence = pk_and_sequence_for(table)

  if pk
    if sequence
      quoted_sequence = quote_table_name(sequence)

      select_value "      SELECT setval('\#{quoted_sequence}', \#{value})\n      end_sql\n    else\n      @logger.warn \"\#{table} has primary key \#{pk} with no default sequence\" if @logger\n    end\n  end\nend\n", 'SCHEMA'

#table_exists?(name) ⇒ Boolean

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)

Returns:

  • (Boolean) 


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

#tables(name = nil) ⇒ Object

Returns the list of all tables in the schema search path or a specified schema.



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 90

def tables(name = nil)
  query("    SELECT tablename\n    FROM pg_tables\n    WHERE schemaname = ANY (current_schemas(false))\n  SQL\nend\n", 'SCHEMA').map { |row| row[0] }

#type_to_sql(type, limit = nil, precision = nil, scale = nil) ⇒ Object

Maps logical Rails types to PostgreSQL-specific data types.



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# File 'lib/active_record/connection_adapters/postgresql/schema_statements.rb', line 534

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