1 Pertemuan 16 Object Query Language (Lanjutan bagian 3) Matakuliah: M0174/OBJECT ORIENTED DATABASE Tahun: 2005 Versi: 1/0

2 Learning Outcomes Pada akhir pertemuan ini, diharapkan mahasiswa akan mampu : Mahasiswa dapat Menghasilkan query language dalam object data model (C3)

3 Outline Materi Retrieving Creating structured Creating mutable Creating collections Conversion

4 Retrieving Definition Example –Return the existing Product object with the object name, best_seller best_seller –Return a string literal, which is the value of the name attribute of the product object called best_seller best_seller.name

5 Retrieving –Return a collection-object which contains the existing mutable product object for the bat bike product select p from products p where p.name = “bat bike”;

6 Retrieving –Return a literal collection-object containing string literals which are the values of the colour attribute of mutable product object select p.colour from products p

7 Creating structured Structured-literal (set, bag, list, array, and structure-literal) can be created using the object constructor operators, struct, set, bag, list, and array Example

8 Creating structured ::= struct ([ : [, : ] *] ) | set ([ [, *] )| bag ([ [, *] )| list ([ [, *] )| array ([ [, *] )

9 Creating mutable Type names are used as constructor operators to create new mutable objects of the specified type Example

10 Creating collections The select…from…where form of OQL has number of variations which can be used to return different types of collection object –The general form –The distinct –The group by –An order by Example

11 Conversion Listtoset Distinct Element Flatten Example

12 SUMMARY OQL can retrieve existing objects and can also create new ones New objects can be created using the constructors, set, bag, list, array, and struct OQL also includes operators for changing the type of an object (listtoset, distinct,element, and flatten)