PPT On IBM DB2
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Description:
1. IBM DB2
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2. Introduction
First Release in 1982
DB2 is Relational DBMS (R-DBMS)
Relational Data or Binary Data
Support Pure XML for Easy Storage and Retrieval
Support Both GUI and CLI
3. DB2 Instance
A DB2 instance is a logical database server environment. There can be multiple DB2 instances on a server. Multiple Databases can be created within a DB2 instance.
The default instance for a particular system is defined by the ‘DB2INSTANCE’ environment variable. Initially for Windows default is ‘DB2’ and for Linux/Unix it is ‘db2inst1’.
4. DB2 tablespace
A tablespace is a logical layer between data and storage space.
Tables, regular data, indexes and long data reside in tablespace.
SYSCATSPACE: where the DB2 system kept tracks of all of the metadata associated with DB2 objects .
TEMPSPACE1: A temporary work area where DB2 can place intermediate results.
USERSPACE1: A place where all user objects (tables, indexes) reside by default.
5. Constraints
Primary Keys: Used to enforce uniqueness on one or set of column values.
Foreign Keys: Used to establish a referential relationship b/w two tables, can be referred as Child and Parent.
Unique Keys: Used to enforce on one or set of column values. A table can have multiple unique keys.
Checked Constraints: They are used to enforce rules for those table column so that data inserted or updated in those columns meets the conditions predefined in the check constraints.
6. DB2 Object: Table
All data is stored in tables in the database. A table consists of one or more columns of various data types. The data is stored in rows or records.
May be defined using:
The CREATE TABLE SQL statement
A GUI tool, the DB2 Control Center
7. DB2 Object: view
A view provides a transparent view of the data in underlying tables. Contains no data itself. Appears just like a table to the user. Can also be used to restrict which rows and columns can be viewed or updated.
You can create a view on an existing table (or tables) or on another view or any combination. A view defined on another view is called a nested view.
CREATE VIEW nonfictionbooks AS
SELECT * FROM books WHERE booktype = 'N‘
8. DB2 Object: Triggers
A trigger is used to define a set of actions that are to be executed whenever an insert, update, or delete operation is performed against a table or updatable view.
Like constraints, triggers are often used to enforce data integrity and business rules.
Unlike constraints, triggers can also be used to update other tables, automatically generate or transform values for inserted or updated rows, and invoke functions to perform tasks such as issuing errors or alerts.
9. Thank You
