3) working with databases and database objects ppt
TRANSCRIPT
IBM DB2 9
Section -3) Working with Working with
Databases and Database ObjectsDatabases and Database Objects
© 2008 IBM Corporation
Amit Daharwal
IT Specialist – IBM Academic Initiative
IBM DB2 9
Section 3 Section 3 -- Working with Databases and Working with Databases and
Database Objects (17%)Database Objects (17%)
��Ability to identify and connect to DB2 servers Ability to identify and connect to DB2 servers
and databasesand databases
��Ability to identify DB2 objectsAbility to identify DB2 objects
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��Ability to identify DB2 objectsAbility to identify DB2 objects
��Knowledge of basic characteristics and Knowledge of basic characteristics and
properties of DB2 objectsproperties of DB2 objects
��Given a DDL SQL statement, ability to identify Given a DDL SQL statement, ability to identify
results (ability to create DB2 objects)results (ability to create DB2 objects)
IBM DB2 9
Servers, Instances, and Databases
�During the installation process, program files for a background
process known as the DB2 Database Manager are physically
copied to a specific location on the server.
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�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.
IBM DB2 9
More on instances
�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’.
�DB2 9 Instance Management Commands:
Command Purpose
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db2icrt [InstanceName] Creates a new instance
db2idrop [InstanceName] Deletes (drops) an existing instance
db2ilist Lists all instances that have been defined
db2start Starts the DB2 Database Manager background
processes for the current instance
db2stop Stops the DB2 Database Manager background
processes for the current instance
IBM DB2 9
DB2 Storage Model
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IBM DB2 9
DB2 Storage Model
�A database is created within an instance.
�There may be multiple databases managed by a DB2
instance
�Logical storage model:
�Tables are made up of columns and rows
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�Tables are placed into table spaces
�Table spaces can contain more than one table
�Physical storage model:
�Container is a physical storage device
�Can be a directory, a device, or a file
�Container is assigned to a table space
IBM DB2 9
Tablespaces
�A tablespace is a logical layer between data and storage
devices.
�Consists of one or more containers.
�Tables, regular data, indexes, and long data reside in
tablespaces
�SQL: CREATE / DROP / ALTER TABLESPACE
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�SQL: CREATE / DROP / ALTER TABLESPACE
�To display Table space info:
�LIST TABLESPACES [SHOW DETAIL]
�Details about containers can be obtained with following
command.
�LIST TABLESPACE CONTAINERS FOR tablespace_id
[SHOW DETAIL]
IBM DB2 9
Types of Tablespaces
�System-Managed Space (SMS):
�OS’s file system manager allocates and manages the space.
�Database-Managed Space (DMS):
�Here, the database manager controls the storage space.
�Automatic Storage With DMS:
�Databases that are enabled for automatic storage have a set
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�Databases that are enabled for automatic storage have a set
of one or more storage paths associated with them.
�A table space can be defined as "managed by automatic
storage" and its containers assigned and allocated by DB2
based on those storage paths.
�You cannot enable/disable automatic storage once it is
defined for database.
�Default type in DB2 9.
IBM DB2 9
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IBM DB2 9
Database
� The database contains following objects:
�Tables, views, indexes, schemas, Locks, triggers, stored
procedures, packages, Buffer pools, log files, table spaces
� Tools, which can help you create DB2 9 database are First
Steps, Control Center [ Using GUI Wizard ] and Command
Line Processor (CLP).
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Line Processor (CLP).
� Some database commands -
CREATE DATABASE
<dbname>
To create a database. (Database name
can not begin with "SYS", "DBM", or "IBM“)
CONNECT TO <dbname> To connect to a database
CONNECT RESET To terminate connection
DROP DATABASE <dbname> To drop database
IBM DB2 9
With database, DB2 automatically creates
� Three table spaces are created.
� SYSCATSPACE - This is where the DB2 system
catalog is kept that tracks all of the metadata
associated with DB2 objects.
� TEMPSPACE1 – A temporary work area where
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� TEMPSPACE1 – A temporary work area where
DB2 can place intermediate results.
� USERSPACE1 – A place where all user objects
(tables, indexes) reside by default.
� Configuration information (DB CFG)
� Log files, History files etc.
IBM DB2 9
Cataloging
�DB2 automatically catalogs databases when they are
created. It catalogs an entry for the DB in the local database
directory and another entry in the system database directory.
�Without catalog information, an application cannot connect to a
DB. DB2 has multiple directories that are used to access DBs.
�The database directory contains a list and pointer to where
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�The database directory contains a list and pointer to where
all the known databases can be found. (list db directory)
�The node directory contains information relating to how and
where remote instances can be found. (list node directory)
�The Database Connection Services (DCS) Directory
contains information relating to how and where databases on
DRDA systems can be found. (list dcs directory)
IBM DB2 9
3 ways of cataloging a database at a client�Automated configuration using discovery. This method is normally used to configure small numbers of clients.
�Search discovery- Client searches for servers on the network
�Known discovery- one particular server is queried for information about the instances and their databases
�Automated configuration using access profiles. This
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�Automated configuration using access profiles. This method is used to configure a large number of clients.
�Server profiles- created from DB2 servers, contains information about all the instances and databases of server
�Client profiles- used to duplicat the cataloged databases and/or the client settings from one client to another
�Manual configuration used to exploit some advanced options not available using automation
IBM DB2 9
Get connected using Configuration Assistant
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IBM DB2 9
Configuration Assistant - Search the Network (1)
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IBM DB2 9
Configuration Assistant - Search the Network (2)
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IBM DB2 9
Configuration Assistant - Search the Network (3)
17Click
IBM DB2 9
Configuration Assistant - Search the Network (4)
Enter User ID and
Password through
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Click
Password through
which you want to
connect and click
Test Connection
Result tab will show
connection results.
IBM DB2 9
Configuration Assistant – Manually (1)
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Enter IP address or
Machine Name Default port on
Windows : 50000
Click
IBM DB2 9
Configuration Assistant - Manually (2)
Choose protocol
(e.g. TCP/IP)
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Click
IBM DB2 9
Configuration Assistant – Manually (3)
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Enter Database name
Click
Enter : Alias of database
which don't exist on client
IBM DB2 9
Configuration Assistant – Manually (4)
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Click
IBM DB2 9
Configuration Assistant - Manually (5)
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Click
IBM DB2 9
Configuration Assistant – Manually (6)
24Click
IBM DB2 9
Configuration Assistant - Manually (7)
Enter User ID and
Password through
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Click
Password through
which you want to
connect and click
Test Connection
Result tab will show
connection results.
IBM DB2 9
Client/Server Connectivity using CLP
�To illustrate connectivity ,we will use a scenario:
� INSTANCE is DB2
�DATABASE is SAMPLE
� IP ADDRESS is 9.186.128.141
�Settings on the server:
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�Value of DB2COMM is tcpip
�Services file contains valid TCP/IP port number , in our case
default is 50000
�Windows client machine:
�Catalog the server
�Catalog the database
IBM DB2 9
CLP - Cataloging the Server and Database
�Cataloging a server:
�CATALOG TCPIP NODE db2server
REMOTE 9.186.128.141 SERVER 50000
�Cataloging a database:
�CATALOG DATABASE sample AS srv_samp
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�CATALOG DATABASE sample AS srv_samp
AT NODE db2server
�UNCATALOG DATABASE sample
�Cataloging a DCS database (DRDA Server)
�CATALOG DCS DATABASE test_db AS dsn_db
WITH "DB2 z/OS database"
IBM DB2 9
Database Objects - Tables
�A Table is an unordered set of rows. Rows consist of columns.
Each column is based on a data type. Types of tables can be:
�Base tables: User-defined tables designed to hold persistent
user data, created with the CREATE TABLE SQL statement.
�Temporary (Derived) tables: Tables populated with rows
retrieved from one or more base tables in response to a query.
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retrieved from one or more base tables in response to a query.
�Temporary (Declared) tables: User-defined tables used to
hold non-persistent data temporarily, on behalf of a single
application. These tables are explicitly created by an
application when they are needed and implicitly destroyed
when the application terminates its last database connection.
Declared temporary table is created with the DECLARE
GLOBAL TEMPORARY TABLE statement.
IBM DB2 9
Database Objects - Views
�Views can be seen as virtual tables derived from one
or more tables or views and
�Created to limit access to sensitive data while allowing
more general access to other data.
�Views do not contain real data.
�Can be deletable, updatable, insertable, and read-only.
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�Can be deletable, updatable, insertable, and read-only.
�When changes are made to data through a view, the data
is changed in underlying table itself.
�Can be used interchangeably with tables when retrieving
data.
�CREATE VIEW dept_view AS
SELECT * FROM department
IBM DB2 9
Database Objects – Aliases & Nicknames
�An alias is simply an alternate name for a table or
view.
�Like tables and views, an alias can be created,
dropped, and have comments associated with it.
�Aliases can also be created for nicknames that refer
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�Aliases can also be created for nicknames that refer
to tables or views found on federated systems.
�Aliases are publicly referenced names, so no special
authority or privilege is required to use them.
�CREATE ALIAS empinfo FOR employees
IBM DB2 9
Database Objects – Sequences
�A sequence is an object that is used to generate data values
automatically. Unlike an identity column, a sequence is not tied
to any specific column or any specific table.
�Values generated can be any exact numeric data type that
has a scale of zero (SMALLINT, BIGINT, INTEGER, or
DECIMAL).The default increment value is 1.
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DECIMAL).The default increment value is 1.
�The PREVIOUS VALUE expression returns the most recently
generated value for the specified sequence, while the NEXT
VALUE expression returns the next sequence value.
�CREATE SEQUENCE emp_id START WITH 100
INCREMENT BY 10 CACHE 5
IBM DB2 9
Database Objects – 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
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�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.
�Ex. CREATE TRIGGER pay_raise BEFORE UPDATE ON employees FOR EACH ROW SET new.salary = salary * 1.1
IBM DB2 9
Database Objects – Stored Procedures
�An SQL stored procedure is composed entirely of SQL
statements. It is created by executing one form of the CREATE
PROCEDURE SQL statement.
�When an SQL stored procedure is used to implement a
business rule, the logic can be incorporated into any
application simply by invoking the stored procedure.
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application simply by invoking the stored procedure.
�An external stored procedure is a stored procedure that is
written using a high-level programming language such as C,
C++, Java, or COBOL.
�External stored procedures can be more powerful than SQL
stored procedures because they can take advantage of system
calls and administrative APIs along with SQL statements.
IBM DB2 9
Calling a Stored Procedure
CREATE PROCEDURE get_sales (IN quota INTEGER, OUT retcode CHAR(5)) DYNAMIC RESULT SETS 1 LANGUAGE SQL
BEGIN
DECLARE sqlstate CHAR(5); DECLARE sales_results CURSOR WITH RETURN FOR SELECT sales_person, SUM(sales) AS total_sales
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SELECT sales_person, SUM(sales) AS total_sales FROM sales GROUP BY sales_person
HAVING SUM(sales) > quota; DECLARE EXIT HANDLER FOR SQLEXCEPTION SET retcode = sqlstate; OPEN sales_results; SET retcode = sqlstate;
END
�CALL get_sales (25, ?)
IBM DB2 9
Database Objects – UDFs
�User-defined functions (UDFs) are special objects that are
used to extend and enhance the support provided by the built-
in functions available with DB2 9.
�Unlike DB2's built-in functions, user-defined functions can take
advantage of system calls and DB2's administrative APIs.
�User-defined functions are created (or registered) by executing
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�User-defined functions are created (or registered) by executing
the CREATE FUNCTION SQL statement.
�SQL Scalar, Table, or Row. constructed using only SQL
statements and can return a value, row or table.
�External Scalar/Table written using a high-level programming
language such as C, C++, or Java and returns a single value
or table.
IBM DB2 9
Invoking User-Defined Functions
CREATE FUNCTION jobemployees (job VARCHAR(8))
RETURNS TABLE (empno CHAR(6),
firstname VARCHAR(12), lastname VARCHAR(15))
LANGUAGE SQL READS SQL DATA
NO EXTERNAL ACTION DETERMINISTIC
RETURN SELECT empno, firstnme, lastname
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RETURN SELECT empno, firstnme, lastname
FROM employee
WHERE employee.job = jobemployees.job;
Calling function -
�SELECT * FROM TABLE (jobemployees('CLERK'))
�SELECT temp AS tempf, convert_temp(temp, 'F') AS tempc FROM climate_info
IBM DB2 9
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IBM DB2 9
1) While attempting to connect to a database stored on an iSeries
server from a Windows client, the following message was displayed:
�SQL1013N The database alias name or
database name "TEST_DB" could not be found.
�Which of the following actions can be used to help determine why
this message was displayed?
� A. Execute the LIST REMOTE DATABASES command on the
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� A. Execute the LIST REMOTE DATABASES command on the
server; look for an entry for the TEST_DB database
� B. Execute the LIST DCS DIRECTORY command on the server;
look for an entry for the TEST_DB database
� C. Execute the LIST REMOTE DATABASES command on the client;
look for an entry for the TEST_DB database
� D. Execute the LIST DCS DIRECTORY command on the client; look
for an entry for the TEST_DB database
IBM DB2 9
2) A database named TEST_DB resides on a z/OS system and listens on
port 446. The TCP/IP address for this system is 192.168.10.20 and the
TCP/IP host name is MYHOST. Which of the following commands is
required to make this database accessible to a Linux client?
� A. CATALOG TCPIP NODE zos_srvr REMOTE myhost SERVER
192.168.10.20;CATALOG DATABASE zos_db AS test_db AT NODE
zos_srvr;CATALOG DCS DATABASE zos_db AS test_db;
� B. CATALOG TCPIP NODE zos_srvr REMOTE myhost SERVER
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� B. CATALOG TCPIP NODE zos_srvr REMOTE myhost SERVER
192.168.10.20;CATALOG DCS DATABASE zos_db AS test_db AT
NODE zos_srvr;
� C. CATALOG TCPIP NODE zos_srvr REMOTE myhost SERVER
446;CATALOG DCS DATABASE zos_db AS test_db AT NODE
zos_srvr;
� D. CATALOG TCPIP NODE zos_srvr REMOTE myhost SERVER
446;CATALOG DATABASE zos_db AS test_db AT NODE
zos_srvr;CATALOG DCS DATABASE zos_db AS test_db;
IBM DB2 9
3) In which of the following scenarios would a stored procedure
be beneficial?
�A. An application running on a remote client needs to be able
to convert degrees Celsius to degrees Fahrenheit and vice
versa
�B. An application running on a remote client needs to collect
three input values, perform a calculation using the values
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three input values, perform a calculation using the values
provided, and store the input data, along with the results of the
calculation in two different base tables
�C. An application running on a remote client needs to track
every modification made to a table that contains sensitive data
�D. An application running on a remote client needs to ensure
that every new employee that joins the company is assigned a
unique, sequential employee number
IBM DB2 9
4) If the following SQL statements are executed in the order shown:
CREATE TABLE orders (order_num INTEGER NOT NULL,
Buyer_name VARCHAR(35), Amount NUMERIC(5,2));
CREATE UNIQUE INDEX idx_orderno ON orders(order_num);
Which of the following describes the resulting behavior?
� A. Every ORDER_NUM value entered must be unique; whenever the
ORDERS table is queried rows should be displayed in order of
increasing ORDER_NUM values
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increasing ORDER_NUM values
� B. Every ORDER_NUM value entered must be unique; whenever the
ORDERS table is queried rows will be displayed in no particular order
� C. Duplicate ORDER_NUM values are allowed; no other index can be
created for the ORDERS table that reference the ORDER_NUM column
� D. Every ORDER_NUM value entered must be unique; no other index
can be created for the ORDERS table that reference the ORDER_NUM
column
IBM DB2 9
5) An alias can be an alternate name for which
two of the following DB2 objects?
�A. Sequence
�B. Trigger
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B. Trigger
�C. View
�D. Schema
�E. Table
IBM DB2 9
6) Which of the following DB2 objects can be
referenced by an INSERT statement to
generate values for a column?
�A. Sequence
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�B. Identity column
�C. Trigger
�D. Table function
IBM DB2 9
7) Which of the following is NOT an attribute of
Declared Global Temporary Tables (DGTTs)?
�A. Each application that defines a DGTT has its own
instance of the DGTT
�B. Two different applications cannot create DGTTs
that have the same name
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that have the same name
�C. DGTTs can only be used by the application that
creates them, and only for the life of the application
�D. Data stored in a DGTT can exist across transaction
boundaries
IBM DB2 9
8) Which of the following is an accurate statement
about packages?
�A. Packages provide a logical grouping of database
objects.
�B. Packages contain control structures that are
considered the bound form for SQL statements
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considered the bound form for SQL statements
�C. Packages describe the objects in a DB2 database
and their relationship to each other
�D. Packages may be used during query optimization
to improve the performance for a subset of SELECT
queries
IBM DB2 9
9) Which of the following events will NOT cause
a trigger to be activated?
�A. A select operation
�B. An insert operation
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�B. An insert operation
�C. An update operation
�D. A delete operation
IBM DB2 9
10) Which of the following DB2 objects is NOT
considered executable using SQL?
�A. Routine
�B. Function
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�B. Function
�C. Procedure
�D. Trigger
IBM DB2 9
11) Which of the following is NOT an accurate
statement about views?
�A. Views are publicly referenced names and no
special authority or privilege is needed to use them.
�B. Views can be used to restrict access to columns in
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�B. Views can be used to restrict access to columns in
a base table that contain sensitive data
�C. Views can be used to store queries that multiple
applications execute on a regular basis in a database
�D. Views support INSTEAD OF triggers
IBM DB2 9
12) Which of the following SQL statements can be
used to create a DB2 object to store numerical data
as EURO data?
�A. CREATE NICKNAME euro FOR DECIMAL (9,3)
�B. CREATE ALIAS euro FOR DECIMAL (9,3)
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�B. CREATE ALIAS euro FOR DECIMAL (9,3)
�C. CREATE DISTINCT TYPE euro AS DECIMAL
(9,3)
�D. CREATE DATA TYPE euro AS DECIMAL (9,3)
IBM DB2 9
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