Module: Sequel::Postgres::DatabaseMethods

Included in:
Database
Defined in:
lib/sequel_core/adapters/shared/postgres.rb

Overview

Methods shared by Database instances that connect to PostgreSQL.

Constant Summary collapse

PREPARED_ARG_PLACEHOLDER = 
'$'.lit.freeze
RE_CURRVAL_ERROR = 
/currval of sequence "(.*)" is not yet defined in this session|relation "(.*)" does not exist/.freeze
SQL_BEGIN = 
'BEGIN'.freeze
SQL_SAVEPOINT = 
'SAVEPOINT autopoint_%d'.freeze
SQL_COMMIT = 
'COMMIT'.freeze
SQL_ROLLBACK_TO_SAVEPOINT = 
'ROLLBACK TO SAVEPOINT autopoint_%d'.freeze
SQL_ROLLBACK = 
'ROLLBACK'.freeze
SQL_RELEASE_SAVEPOINT = 
'RELEASE SAVEPOINT autopoint_%d'.freeze
SYSTEM_TABLE_REGEXP = 
/^pg|sql/.freeze

Instance Method Summary collapse

Instance Method Details

#create_function(*args) ⇒ Object

Creates the function in the database. See create_function_sql for arguments.



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# File 'lib/sequel_core/adapters/shared/postgres.rb', line 160

def create_function(*args)
  self << create_function_sql(*args)
end

#create_function_sql(name, definition, opts = {}) ⇒ Object

SQL statement to create database function. Arguments:

  • name : name of the function to create

  • definition : string definition of the function, or object file for a dynamically loaded C function.

  • opts : options hash:

    • :args : function arguments, can be either a symbol or string specifying a type or an array of 1-3 elements:

      • element 1 : argument data type

      • element 2 : argument name

      • element 3 : argument mode (e.g. in, out, inout)

    • :behavior : Should be IMMUTABLE, STABLE, or VOLATILE. PostgreSQL assumes VOLATILE by default.

    • :cost : The estimated cost of the function, used by the query planner.

    • :language : The language the function uses. SQL is the default.

    • :link_symbol : For a dynamically loaded see function, the function’s link symbol if different from the definition argument.

    • :returns : The data type returned by the function. If you are using OUT or INOUT argument modes, this is ignored. Otherwise, if this is not specified, void is used by default to specify the function is not supposed to return a value.

    • :rows : The estimated number of rows the function will return. Only use if the function returns SETOF something.

    • :security_definer : Makes the privileges of the function the same as the privileges of the user who defined the function instead of the privileges of the user who runs the function. There are security implications when doing this, see the PostgreSQL documentation.

    • :set : Configuration variables to set while the function is being run, can be a hash or an array of two pairs. search_path is often used here if :security_definer is used.

    • :strict : Makes the function return NULL when any argument is NULL.



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# File 'lib/sequel_core/adapters/shared/postgres.rb', line 184

def create_function_sql(name, definition, opts={})
  args = opts[:args]
  if !opts[:args].is_a?(Array) || !opts[:args].any?{|a| Array(a).length == 3 and %w'OUT INOUT'.include?(a[2].to_s)}
    returns = opts[:returns] || 'void'
  end
  language = opts[:language] || 'SQL'
  "  CREATE\#{' OR REPLACE' if opts[:replace]} FUNCTION \#{name}\#{sql_function_args(args)}\n  \#{\"RETURNS \#{returns}\" if returns}\n  LANGUAGE \#{language}\n  \#{opts[:behavior].to_s.upcase if opts[:behavior]}\n  \#{'STRICT' if opts[:strict]}\n  \#{'SECURITY DEFINER' if opts[:security_definer]}\n  \#{\"COST \#{opts[:cost]}\" if opts[:cost]}\n  \#{\"ROWS \#{opts[:rows]}\" if opts[:rows]}\n  \#{opts[:set].map{|k,v| \" SET \#{k} = \#{v}\"}.join(\"\\n\") if opts[:set]}\n  AS \#{literal(definition.to_s)}\#{\", \#{literal(opts[:link_symbol].to_s)}\" if opts[:link_symbol]}\n  END\nend\n"

#create_language(*args) ⇒ Object

Create the procedural language in the database. See create_language_sql for arguments.



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# File 'lib/sequel_core/adapters/shared/postgres.rb', line 205

def create_language(*args)
  self << create_language_sql(*args)
end

#create_language_sql(name, opts = {}) ⇒ Object

SQL for creating a procedural language. Arguments:

  • name : Name of the procedural language (e.g. plpgsql)

  • opts : options hash:

    • :handler : The name of a previously registered function used as a call handler for this language.

    • :trusted : Marks the language being created as trusted, allowing unprivileged users to create functions using this language.

    • :validator : The name of previously registered function used as a validator of functions defined in this language.



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# File 'lib/sequel_core/adapters/shared/postgres.rb', line 215

def create_language_sql(name, opts={})
  "CREATE#{' TRUSTED' if opts[:trusted]} LANGUAGE #{name}#{" HANDLER #{opts[:handler]}" if opts[:handler]}#{" VALIDATOR #{opts[:validator]}" if opts[:validator]}"
end

#create_trigger(*args) ⇒ Object

Create a trigger in the database. See create_trigger_sql for arguments.



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# File 'lib/sequel_core/adapters/shared/postgres.rb', line 220

def create_trigger(*args)
  self << create_trigger_sql(*args)
end

#create_trigger_sql(table, name, function, opts = {}) ⇒ Object

SQL for creating a database trigger. Arguments:

  • table : the table on which this trigger operates

  • name : the name of this trigger

  • function : the function to call for this trigger, which should return type trigger.

  • opts : options hash:

    • :after : Calls the trigger after execution instead of before.

    • :args : An argument or array of arguments to pass to the function.

    • :each_row : Calls the trigger for each row instead of for each statement.

    • :events : Can be :insert, :update, :delete, or an array of any of those. Calls the trigger whenever that type of statement is used. By default, the trigger is called for insert, update, or delete.



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# File 'lib/sequel_core/adapters/shared/postgres.rb', line 234

def create_trigger_sql(table, name, function, opts={})
  events = opts[:events] ? Array(opts[:events]) : [:insert, :update, :delete]
  whence = opts[:after] ? 'AFTER' : 'BEFORE'
  "CREATE TRIGGER #{name} #{whence} #{events.map{|e| e.to_s.upcase}.join(' OR ')} ON #{quote_schema_table(table)}#{' FOR EACH ROW' if opts[:each_row]} EXECUTE PROCEDURE #{function}(#{Array(opts[:args]).map{|a| literal(a)}.join(', ')})"
end

#default_schema ⇒ Object

The default schema to use if none is specified (default: public)



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# File 'lib/sequel_core/adapters/shared/postgres.rb', line 241

def default_schema
  @default_schema ||= :public
end

#drop_function(*args) ⇒ Object

Drops the function from the database. See drop_function_sql for arguments.



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# File 'lib/sequel_core/adapters/shared/postgres.rb', line 246

def drop_function(*args)
  self << drop_function_sql(*args)
end

#drop_function_sql(name, opts = {}) ⇒ Object

SQL for dropping a function from the database. Arguments:

  • name : name of the function to drop

  • opts : options hash:

    • :args : The arguments for the function. See create_function_sql.

    • :cascade : Drop other objects depending on this function.

    • :if_exists : Don’t raise an error if the function doesn’t exist.



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# File 'lib/sequel_core/adapters/shared/postgres.rb', line 256

def drop_function_sql(name, opts={})
  "DROP FUNCTION#{' IF EXISTS' if opts[:if_exists]} #{name}#{sql_function_args(opts[:args])}#{' CASCADE' if opts[:cascade]}"
end

#drop_language(*args) ⇒ Object

Drops a procedural language from the database. See drop_language_sql for arguments.



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# File 'lib/sequel_core/adapters/shared/postgres.rb', line 261

def drop_language(*args)
  self << drop_language_sql(*args)
end

#drop_language_sql(name, opts = {}) ⇒ Object

SQL for dropping a procedural language from the database. Arguments:

  • name : name of the procedural language to drop

  • opts : options hash:

    • :cascade : Drop other objects depending on this function.

    • :if_exists : Don’t raise an error if the function doesn’t exist.



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# File 'lib/sequel_core/adapters/shared/postgres.rb', line 270

def drop_language_sql(name, opts={})
  "DROP LANGUAGE#{' IF EXISTS' if opts[:if_exists]} #{name}#{' CASCADE' if opts[:cascade]}"
end

#drop_table(*names) ⇒ Object

Remove the cached entries for primary keys and sequences when dropping a table.



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# File 'lib/sequel_core/adapters/shared/postgres.rb', line 275

def drop_table(*names)
  names.each do |name|
    name = quote_schema_table(name)
    @primary_keys.delete(name)
    @primary_key_sequences.delete(name)
  end
  super
end

#drop_table_sql(name) ⇒ Object

Always CASCADE the table drop



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# File 'lib/sequel_core/adapters/shared/postgres.rb', line 285

def drop_table_sql(name)
  "DROP TABLE #{quote_schema_table(name)} CASCADE"
end

#drop_trigger(*args) ⇒ Object

Drops a trigger from the database. See drop_trigger_sql for arguments.



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# File 'lib/sequel_core/adapters/shared/postgres.rb', line 290

def drop_trigger(*args)
  self << drop_trigger_sql(*args)
end

#drop_trigger_sql(table, name, opts = {}) ⇒ Object

SQL for dropping a trigger from the database. Arguments:

  • table : table from which to drop the trigger

  • name : name of the trigger to drop

  • opts : options hash:

    • :cascade : Drop other objects depending on this function.

    • :if_exists : Don’t raise an error if the function doesn’t exist.



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# File 'lib/sequel_core/adapters/shared/postgres.rb', line 300

def drop_trigger_sql(table, name, opts={})
  "DROP TRIGGER#{' IF EXISTS' if opts[:if_exists]} #{name} ON #{quote_schema_table(table)}#{' CASCADE' if opts[:cascade]}"
end

#index_definition_sql(table_name, index) ⇒ Object

PostgreSQL specific index SQL.



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# File 'lib/sequel_core/adapters/shared/postgres.rb', line 305

def index_definition_sql(table_name, index)
  index_name = index[:name] || default_index_name(table_name, index[:columns])
  expr = literal(Array(index[:columns]))
  unique = "UNIQUE " if index[:unique]
  index_type = index[:type]
  filter = index[:where] || index[:filter]
  filter = " WHERE #{filter_expr(filter)}" if filter
  case index_type
  when :full_text
    cols = Array(index[:columns]).map{|x| :COALESCE[x, '']}.sql_string_join(' ')
    expr = "(to_tsvector(#{literal(index[:language] || 'simple')}, #{literal(cols)}))"
    index_type = :gin
  when :spatial
    index_type = :gist
  end
  "CREATE #{unique}INDEX #{index_name} ON #{table_name} #{"USING #{index_type} " if index_type}#{expr}#{filter}"
end

#locks ⇒ Object

Dataset containing all current database locks



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# File 'lib/sequel_core/adapters/shared/postgres.rb', line 324

def locks
  dataset.from(:pg_class, :pg_locks).
    select(:pg_class__relname, :pg_locks.*).
    filter(:pg_class__relfilenode=>:pg_locks__relation)
end

#primary_key(table, server = nil) ⇒ Object

Return primary key for the given table.



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# File 'lib/sequel_core/adapters/shared/postgres.rb', line 331

def primary_key(table, server=nil)
  synchronize(server){|conn| primary_key_for_table(conn, table)}
end

#rename_table_sql(name, new_name) ⇒ Object

SQL DDL statement for renaming a table. PostgreSQL doesn’t allow you to change a table’s schema in a rename table operation, so speciying a new schema in new_name will not have an effect.



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# File 'lib/sequel_core/adapters/shared/postgres.rb', line 337

def rename_table_sql(name, new_name)
  "ALTER TABLE #{quote_schema_table(name)} RENAME TO #{quote_identifier(schema_and_table(new_name).last)}"
end

#serial_primary_key_options ⇒ Object

PostgreSQL uses SERIAL psuedo-type instead of AUTOINCREMENT for managing incrementing primary keys.



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# File 'lib/sequel_core/adapters/shared/postgres.rb', line 343

def serial_primary_key_options
  {:primary_key => true, :type => :serial}
end

#server_version(server = nil) ⇒ Object

The version of the PostgreSQL server, used for determining capability.



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# File 'lib/sequel_core/adapters/shared/postgres.rb', line 348

def server_version(server=nil)
  return @server_version if @server_version
  @server_version = synchronize(server) do |conn|
    (conn.server_version rescue nil) if conn.respond_to?(:server_version)
  end
  unless @server_version
    m = /PostgreSQL (\d+)\.(\d+)\.(\d+)/.match(get(:version[]))
    @server_version = (m[1].to_i * 10000) + (m[2].to_i * 100) + m[3].to_i
  end
  @server_version
end

#table_exists?(table, opts = {}) ⇒ Boolean

Whether the given table exists in the database

Options:

  • :schema - The schema to search (default_schema by default)

  • :server - The server to use

Returns:

  • (Boolean) 


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# File 'lib/sequel_core/adapters/shared/postgres.rb', line 365

def table_exists?(table, opts={})
  schema, table = schema_and_table(table)
  opts[:schema] ||= schema
  tables(opts){|ds| !ds.first(:relname=>table.to_s).nil?}
end

#tables(opts = {}) ⇒ Object

Array of symbols specifying table names in the current database. The dataset used is yielded to the block if one is provided, otherwise, an array of symbols of table names is returned.

Options:

  • :schema - The schema to search (default_schema by default)

  • :server - The server to use



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# File 'lib/sequel_core/adapters/shared/postgres.rb', line 378

def tables(opts={})
  ds = self[:pg_class].join(:pg_namespace, :oid=>:relnamespace, 'r'=>:relkind, :nspname=>(opts[:schema]||default_schema).to_s).select(:relname).exclude(:relname.like(SYSTEM_TABLE_REGEXP)).server(opts[:server])
  block_given? ? yield(ds) : ds.map{|r| r[:relname].to_sym}
end

#transaction(server = nil) ⇒ Object

PostgreSQL supports multi-level transactions using save points.



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# File 'lib/sequel_core/adapters/shared/postgres.rb', line 384

def transaction(server=nil)
  synchronize(server) do |conn|
    conn.transaction_depth = 0 if conn.transaction_depth.nil?
    if conn.transaction_depth > 0
      log_info(SQL_SAVEPOINT % conn.transaction_depth)
      conn.execute(SQL_SAVEPOINT % conn.transaction_depth)
    else
      log_info(SQL_BEGIN)
      conn.execute(SQL_BEGIN)
    end
    begin
      conn.transaction_depth += 1
      yield conn
    rescue ::Exception => e
      if conn.transaction_depth > 1
        log_info(SQL_ROLLBACK_TO_SAVEPOINT % [conn.transaction_depth - 1])
        conn.execute(SQL_ROLLBACK_TO_SAVEPOINT % [conn.transaction_depth - 1])
      else
        log_info(SQL_ROLLBACK)
        conn.execute(SQL_ROLLBACK) rescue nil
      end
      transaction_error(e, *CONVERTED_EXCEPTIONS)
    ensure
      unless e
        begin
          if conn.transaction_depth < 2
            log_info(SQL_COMMIT)
            conn.execute(SQL_COMMIT)
          else
            log_info(SQL_RELEASE_SAVEPOINT % [conn.transaction_depth - 1])
            conn.execute(SQL_RELEASE_SAVEPOINT % [conn.transaction_depth - 1])
          end
        rescue => e
          log_info(e.message)
          raise_error(e, :classes=>CONVERTED_EXCEPTIONS)
        end
      end
      conn.transaction_depth -= 1
    end
  end
end