8-1 copyright oracle corporation, 1998. all rights reserved. objects in oracle8 1.object types -...

8-1 Copyright Oracle Corporation, 1998. All rights reserved.

Objects in Oracle8 Objects in Oracle8

1. Object Types - object-relational database

2. Large Objects (LOB) types

1. Object Types - object-relational database

2. Large Objects (LOB) types

Wykład 8Wykład 8


An Object TypeAn Object Type

• Is a user-defined composite datatype

• Encapsulates a data structure along with the methods needed to manipulate it

• Is a user-defined composite datatype

• Encapsulates a data structure along with the methods needed to manipulate it

AttributeAttribute

MethodMethod

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amountamount

HoldHold

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tus

Can

celC

ancel

ShipShip


The Structure of an Object TypeThe Structure of an Object Type

Method bodiesMethod bodies

PublicPublicinterfaceinterface

Private Private implementationimplementation

Attribute declarationsAttribute declarations

Method specificationsMethod specifications

SpecificationSpecification

BodyBody


CREATE TYPE type_name AS OBJECT[(attribute1 datatype, attribute2 datatype, . . .][MEMBER procedure1 | function1 spec, procedure2 | function2 spec, . . .)]

CREATE TYPE type_name AS OBJECT[(attribute1 datatype, attribute2 datatype, . . .][MEMBER procedure1 | function1 spec, procedure2 | function2 spec, . . .)]

SyntaxSyntaxSyntaxSyntax

Creating an Object Type Specification

Creating an Object Type Specification


SyntaxSyntaxSyntaxSyntax

Creating an Object Type BodyCreating an Object Type Body

CREATE TYPE BODY type_name AS [MEMBER procedure1 | function1 body, procedure2 | function2 body, . . .]

CREATE TYPE BODY type_name AS [MEMBER procedure1 | function1 body, procedure2 | function2 body, . . .]


Example: Creating an Object Type Specification

Example: Creating an Object Type Specification

SQL> CREATE TYPE name_typ AS OBJECT(

2 f_name VARCHAR2(25),

3 l_name VARCHAR2(25),

4 initials varchar2(7),

5 MEMBER FUNCTION full_name return varchar2

6 PRAGMA RESTRICT_REFERENCES( full_name,

7 WNDS, RNDS, WNPS, RNPS ));

1

2


Example: Creating an Object Type Body

Example: Creating an Object Type Body

SQL> CREATE TYPE BODY name_typ AS

2 MEMBER FUNCTION full_name RETURN VARCHAR2

3 IS

4 BEGIN

5 RETURN (l_name || ' ' || f_name );

6 END full_name;

7 END;

1


Example: Creating a Complex Object Type Specification

Example: Creating a Complex Object Type Specification

SQL> CREATE TYPE emp_typ AS OBJECT(

2 emp_id NUMBER(7),

3 name name_typ, --datatype is object type

4 street VARCHAR2(25),

5 city VARCHAR2(15),

6 state CHAR(2),

7 zip INTEGER,

8 MEMBER FUNCTION get_name RETURN VARCHAR2

9 PRAGMA RESTRICT_REFERENCES(get_name,

10 WNDS, RNDS, WNPS, RNPS),

11 MEMBER PROCEDURE set_l_name (v_name VARCHAR2));


Example: Creating a Complex Object Type Body

Example: Creating a Complex Object Type Body

SQL> CREATE TYPE BODY emp_typ AS


3 IS

4 BEGIN

5 RETURN (name.l_name ||' '|| name.f_name );

6 END;

7 MEMBER PROCEDURE set_l_name (v_name VARCHAR2)

8 IS

9 BEGIN

10 name.l_name := v_name;

11 END;

12 END;


Obtaining Descriptions of Object Type Methods from the

Data Dictionary

Obtaining Descriptions of Object Type Methods from the

Data DictionaryInformation about objects can be found Information about objects can be found in:in:• USER_OBJECTS

Information about object type methods Information about object type methods can be found in:can be found in:• USER_METHOD_PARAMS

• USER_METHOD_RESULTS

• USER_TYPE_METHODS

Information about objects can be found Information about objects can be found in:in:• USER_OBJECTS

Information about object type methods Information about object type methods can be found in:can be found in:• USER_METHOD_PARAMS

• USER_METHOD_RESULTS

• USER_TYPE_METHODS

• ALL _OBJECTS

• ALL _METHOD_PARAMS

• ALL_ METHOD_RESULTS

• ALL_ TYPE_METHODS


Example: Creating an object table and calling Object

Methods

Example: Creating an object table and calling Object

Methods

SQL> CREATE TABLE name_table OF name_typ;

SQL> INSERT INTO name_table

2 VALUES('Marilyn','Monroe','MM');

SQL> SELECT nt.f_name,nt.name_typ.full_name()

2 FROM name_table nt;


Using the Constructor MethodUsing the Constructor Method

SQL> CREATE TYPE tv_type AS OBJECT (

2 tv_category VARCHAR2(20),

3 screen_size NUMBER(4));

DECLARE

v_new_tv tv_type := tv_type('WEB tv', 32);

v_alt_tv tv_type;

BEGIN

v_alt_tv := tv_type('Big Screen', 72);

END;

SQL> CREATE TABLE tv OF tv_type;

SQL> INSERT INTO tv VALUES(tv_type('Color tv', '28'));

SQL> CREATE TABLE tv OF tv_type;

SQL> INSERT INTO tv VALUES(tv_type('Color tv', '28'));


Manipulating ObjectsManipulating ObjectsObject typeObject type

SQL> CREATE TABLE person_tab OF emp_typ;

Object tableObject table

SQL> CREATE TYPE emp_typ AS OBJECT(

2 emp_id NUMBER(7),

3 name name_typ, --datatype is object type

4 street VARCHAR2(25),

5 city VARCHAR2(15),

6 state CHAR(2),

7 zip INTEGER,


9 PRAGMA RESTRICT_REFERENCES(get_name,

10 WNDS, RNDS, WNPS, RNPS),

11 MEMBER PROCEDURE set_l_name (v_name VARCHAR2));


SELECT VALUE(p) FROM person_tab p WHERE p.l_name LIKE '%BLAKE';

Manipulating Objects: SelectingManipulating Objects: Selecting

SELECT * FROM person_tab p WHERE p.l_name LIKE '%BLAKE';

To return a result set of rows:To return a result set of rows:To return a result set of rows:To return a result set of rows:

To return a result set of objects:To return a result set of objects:To return a result set of objects:To return a result set of objects:


BEGIN INSERT INTO person_tab VALUES(emp_typ(4567,'Christian','Bauwens',. . .)); END;

Manipulating Objects: InsertingManipulating Objects: Inserting

BEGIN INSERT INTO person_tab VALUES(1234,'Ellen','Gravina',. . .);END;

Adding objects to an object table:Adding objects to an object table:Adding objects to an object table:Adding objects to an object table:

Using the constructor for the object type:Using the constructor for the object type:Using the constructor for the object type:Using the constructor for the object type:


BEGIN UPDATE person_tab p SET p = emp_typ(5678,'Charlie','Brown',. . .) WHERE p.l_name = 'Bauwens';END;

Manipulating Objects: UpdatingManipulating Objects: Updating

BEGIN UPDATE person_tab p SET p.street = '25 Elk Street' WHERE p.l_name = 'Gravina';END;

Updating attributes of an object table:Updating attributes of an object table:Updating attributes of an object table:Updating attributes of an object table:

Using the constructor for the object type:Using the constructor for the object type:Using the constructor for the object type:Using the constructor for the object type:


Manipulating Objects: DeletingManipulating Objects: Deleting

Removing objects from an object table:Removing objects from an object table:Removing objects from an object table:Removing objects from an object table:BEGIN DELETE FROM person_tab p WHERE p.street = '25 Elk Street';END;


Reference type of inclusion of objects

Reference type of inclusion of objects

CREATE TYPE Dept_Type AS OBJECT(Name VARCHAR2(10),Loc VARCHAR2(50));

CREATE TABLE Obj_Dept OF Dept_Type;

CREATE TYPE Emp_Type AS OBJECT(Name VARCHAR2(20),Sal Number,Dept_ref REF Dept_Type );

CREATE TABLE Obj_Emp OF Emp_Type(Dept_ref SCOPE IS Obj_Dept);

CREATE TYPE Dept_Type AS OBJECT(Name VARCHAR2(10),Loc VARCHAR2(50));

CREATE TABLE Obj_Dept OF Dept_Type;

CREATE TYPE Emp_Type AS OBJECT(Name VARCHAR2(20),Sal Number,Dept_ref REF Dept_Type );

CREATE TABLE Obj_Emp OF Emp_Type(Dept_ref SCOPE IS Obj_Dept);

CREATE TABLE Rel_emp(id NUMBER PRIMARY KEY,Name VARCHAR2(20),Sal Number,Dept_ref REF Dept_Type SCOPE IS Obj_Dept);

CREATE TABLE Rel_emp(id NUMBER PRIMARY KEY,Name VARCHAR2(20),Sal Number,Dept_ref REF Dept_Type SCOPE IS Obj_Dept);


CollectionsCollections

An attribute or a column may be of a collection type:

1. VARRAY - vector type;

2. TABLE - table type.

An attribute or a column may be of a collection type:

1. VARRAY - vector type;

2. TABLE - table type.


Summary of object typesSummary of object types

• Object types give developers the ability to construct datatypes that were not previously defined.

• An object type has three components:

– Attribute specification

– Method specification

– Method implementation

• Object types can be simple or complex.

• Object types give developers the ability to construct datatypes that were not previously defined.

• An object type has three components:

– Attribute specification

– Method specification

– Method implementation

• Object types can be simple or complex.


Overview - Large ObjectsOverview - Large Objects

Recipe(CLOB)

Photo(BLOB)

MovieMovie(BFILE)(BFILE)


Contrasting LONG and LOB Datatypes

Contrasting LONG and LOB Datatypes

LONG, LONG RAW

Single column per table

Up to 2 Gb

SELECT returns data

Data stored in-line

No object type support

Sequential access to data

LOB

Multiple columns per table

Up to 4 Gb

SELECT returns locator

Data stored in-line or out-of-line

Supports object types

Random access to data


Anatomy of a LOBAnatomy of a LOB

DECLARE lobloc BLOB;BEGIN SELECT col1 INTO lobloc FROM LOB_Table WHERE col2=123; END;

Program with LOB locator handleProgram with LOB locator handle

LOB DataLOB DataTable with Table with

LOB locatorLOB locator


Internal LOBsInternal LOBs

Recipe(CLOB)

Photo(BLOB)


Creating a Table with LOBs: Example

Creating a Table with LOBs: Example

SQL> CREATE TABLE employee 2 (emp_id NUMBER, 3 emp_name VARCHAR2(35), 4 resume CBLOB, 5 picture BLOB);


External LOBsExternal LOBs

Oracle8 provides a BFILE datatype to Oracle8 provides a BFILE datatype to support an external or file-based large support an external or file-based large object as one of the following:object as one of the following:

Oracle8 provides a BFILE datatype to Oracle8 provides a BFILE datatype to support an external or file-based large support an external or file-based large object as one of the following:object as one of the following:

Movie (BFILE)Movie (BFILE)

• Attributes in an object type

• Column values in a table


The Directory AliasThe Directory Alias

Movie (BFILE)Movie (BFILE)

UserUser

DIRECTORYDIRECTORY

lob_path = lob_path = '/oracle/lob/''/oracle/lob/'


Managing LOBsManaging LOBs

• To fully interact with LOBs, file-like interfaces are provided in:

– PL/SQL package DBMS_LOB

– Oracle Call Interface

• The Oracle Server provides some support for LOB management through SQL.

• To fully interact with LOBs, file-like interfaces are provided in:



• The Oracle Server provides some support for LOB management through SQL.


Managing BFILEsManaging BFILEs

• Create OS directory and supply files

• Create Oracle table

• Interact with BFILE using



• Create OS directory and supply files

• Create Oracle table

• Interact with BFILE using




Example: Populating LOBs Using SQL

Example: Populating LOBs Using SQL

To populate a LOB column:To populate a LOB column:

• INSERT row into table, providing either a value, a NULL, or the empty function for the LOB.

• UPDATE row, modifying the column value to a blank RESUME.

To populate a LOB column:To populate a LOB column:

• INSERT row into table, providing either a value, a NULL, or the empty function for the LOB.

• UPDATE row, modifying the column value to a blank RESUME.SQL> UPDATE employee SET resume = 2> (SELECT resume FROM employee 3> WHERE emp_name='Default') 4> AND emp_id = 4508;

SQL> INSERT INTO employee VALUES 2> (7898,'Marilyn Monroe', EMPTY_CLOB(),NULL);


Populating LOBs with PL/SQLPopulating LOBs with PL/SQL

DECLARE -- populate through the PL/SQL package lobloc CLOB; --will serve as the LOB locator text VARCHAR2(2000); amount NUMBER ; offset INTEGER;BEGIN text := 'the text to be written into the LOB'; SELECT resume INTO lobloc -- get LOB handle FROM employee WHERE emp_id = 5887 FOR UPDATE; offset := DBMS_LOB.GETLENGTH(lobloc) + 1; amount := length(text); DBMS_LOB.WRITE ( lobloc, amount, offset, text ); COMMIT; DBMS_OUTPUT.PUT_LINE('You have just written ' || to_char(amount) ||' characters into the LOB'); END;


• Delete rows containing LOBs.

• Disassociate a LOB value from a row.

• Delete rows containing LOBs.

• Disassociate a LOB value from a row.

Example: Removing LOBsExample: Removing LOBs

SQL>DELETE FROM person_tab

2 WHERE pname = 'Opie Griffith';

SQL>UPDATE person_tab SET resume = EMPTY_CLOB()

2 WHERE pname = 'Laura Roshto';


Working with the DBMS_LOB Package

Working with the DBMS_LOB Package

• Much of the work done with LOBs will require use of the provided PL/SQL package, DBMS_LOB.

• DBMS_LOB defines the constants

– DBMS_LOB.LOBMAXSIZE = 4294967294

– file_readonly constant binary_integer:=0

• Much of the work done with LOBs will require use of the provided PL/SQL package, DBMS_LOB.

• DBMS_LOB defines the constants

– DBMS_LOB.LOBMAXSIZE = 4294967294

– file_readonly constant binary_integer:=0


COMPARE

FILEGETNAME

INSTR

GETLENGTH

READ

SUBSTR

FILEEXISTS

FILEISOPEN

The DBMS_LOB PackageThe DBMS_LOB Package

APPEND

COPY

ERASE

TRIM

WRITE

FILECLOSE

FILECLOSEALL

FILEOPEN

Mutators Observers


The DBMS_LOB PackageThe DBMS_LOB Package

• NULL arguments get NULL returns

• Offsets

– BLOB, BFILE: Measured in bytes

– CLOB, NCLOB: Measured in characters

• No negative values for parameters

• NULL arguments get NULL returns

• Offsets

– BLOB, BFILE: Measured in bytes

– CLOB, NCLOB: Measured in characters

• No negative values for parameters


DBMS_LOB READ and WRITEDBMS_LOB READ and WRITE

PROCEDURE READ ( lobsrc IN BFILE|BLOB|CLOB , amount IN OUT BINARY_INTEGER, offset IN INTEGER,buffer OUT RAW|VARCHAR2 )

PROCEDURE WRITE ( lobdst IN OUT BLOB|CLOB, amount IN OUT BINARY_INTEGER, offset IN INTEGER := 1,buffer IN RAW|VARCHAR2 ) -- RAW for BLOB


SummarySummary• Four built-in types for large objects:

BLOB, CLOB, NCLOB, BFILE • LOBs replace LONG and LONG RAW:

New and old types are not compatible• Two storage options for LOBs:

– Stored in the Oracle Server (internal LOBs)

– Stored in external host files (external LOBs)

• DBMS_LOB PL/SQL package provides routines for LOB management.

• Four built-in types for large objects:

BLOB, CLOB, NCLOB, BFILE • LOBs replace LONG and LONG RAW:

New and old types are not compatible• Two storage options for LOBs:

– Stored in the Oracle Server (internal LOBs)

– Stored in external host files (external LOBs)

• DBMS_LOB PL/SQL package provides routines for LOB management.

8-1 copyright oracle corporation, 1998. all rights reserved. objects in oracle8 1.object types -...

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