Object Relational

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Object Relational

Interactions with Oracle


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Outline

Why Object database managementsystems (ODBMSs)?

ODBMS and RDBMS and ORDBMS

Oracle Database Object Relational Oracle Objects

Collection Object Type

Object Type Methods

Inheritance


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Why ODBMS?

The need for storing and manipulating complex data isincreasing. We can not use relational databases tostore this kind of data.

The complex data types appear in several applications:

CAD/CAM

Geometric modeling

Geographical Information Systems

Knowledge-based systems / through frames

Web applications that need to store, index, search andmanipulate diverse objects.

The impedance mismatch becomes apparent whentrying to map these OO language properties to aRDBMS.


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ODBMS ,RDBMS and ORDBMS


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Oracle Database Object Relational


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Object Types

Simple Object Type

A simple object type consists of scalardata types.

Example:CREATE OR REPLACE TYPE Address_objtyp AS OBJECT(

Street VARCHAR2(200),

City VARCHAR2(200),

State CHAR(2),

Zip VARCHAR2(20),

MEMBER FUNCTION formatAsXML RETURN VARCHAR2

);


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Object Types

Reference Object Type A REFis a logical pointer to represent relationships

between class instances.

Example:

CREATE OR REPLACE TYPE LineItem_objtyp AS OBJECT (

LineItemNo NUMBER,

Stock_refREFStockItem_objtyp,

Quantity NUMBER,

Discount NUMBER);

Given a LineItem_objtyp object instance, the price of theitem is easily accessed with the following:

.DEREF(stock_ref).price


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Collection Object Type

Varray An ordered and bounded collection

CREATE OR REPLACE TYPE PhoneList_vartyp

AS VARRAY(10) OF VARCHAR2(25);

Nested tables.

A nested table is an unbounded

and unsorted collection.CREATE OR REPLACE TYPE LineItemList_ntabtyp

AS TABLE OF LineItem_objtyp;


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Composite Object Type

CREATE OR REPLACE TYPE Customer_objtyp AS OBJECT (

CustNo NUMBER,

CustName VARCHAR2(200),

Address_objAddress_objtyp,

PhoneList_varPhoneList_vartyp

) NOT FINAL;


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Composite Object Type

CREATE OR REPLACE TYPE PurchaseOrder_objtyp

AS OBJECT(

PONo NUMBER,

OrderDate DATE,

ShipDate DATE,

Cust_ref REF Customer_objtyp,

LineItemList_ntab LineItemList_ntabtyp,

ShipToAddr_obj Address_objtyp,

MAP MEMBER FUNCTION

getPONo RETURN NUMBER,

MEMBER FUNCTION

sumLineItems RETURN NUMBER

);


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Object Type Methods

Member MethodsCREATE OR REPLACE FUNCTION formatAsXML (customer_id

NUMBER)

Constructor MethodsCREATE OR REPLACE TYPE Customer_objtyp AS OBJECT (

... some code snipped ...

CONSTRUCTOR FUNCTION

customer_objtyp(id IN NUMBER) RETURNSELFAS RESULT,

) NOT FINAL;


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Object Type Methods

Using ConstructorDECLARE

newCustomer customer_objtyp := NULL;BEGIN

newCustomer := customer_objtyp(42,Adams, Douglas,Address_objtyp(123 Handy Road,

Dandyville, CA, 94999),phonelist_vartyp(+1-650-555-1212,

+61-8-9555-1212));

END;


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Comparison Methods

CREATE OR REPLACE TYPE Customer_objtyp AS OBJECT (ORDER MEMBER FUNCTION

compareCustOrders(x IN Customer_objtyp) RETURN INTEGER... some code snipped ...

) NOT FINAL;

CREATE OR REPLACE TYPE BODY customer_objtyp AS

ORDER MEMBER FUNCTION compareCustOrders(x INCustomer_objtyp)

RETURN INTEGER ISBEGINRETURN SELF.CustNo - x.CustNo;

END compareCustOrders;... some code snipped ...

END;


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Inheritance

Using the underkeyword.

CREATE OR REPLACE TYPE OnlineCustomer_objtyp UNDERCustomer_objtyp (

EmailAddress VARCHAR2(50),

MEMBER FUNCTION sendEmail(subject IN VARCHAR2, msg INVARCHAR2) RETURN VARCHAR2

) NOT FINAL;

/

There can be multiple levels in thishierarchy


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Mapping to UML Concepts


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Conclusion

Further reading [1] Object-Oriented Oracle , J.W.Rahayu,

IRM Press, 2005

[2] Professional Oracle Programming,Rick Greenwald, Wrox, 2005 (Chapter21)

Exercise

Using Oracle Object Types with Java ([2],page 501 - 520)

Object Relational

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