Transcript Introduction of Week 2

ITEC 450
MODULE 5 Metadata, Tools,
and Data Warehousing
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Section 1 Metadata Management
METADATA
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Procedures for identifying and defining data ownership
and stewardship
Methods for the collection and storage of metadata
(typically using a repository)
Policies to enforce data stewardship procedures and
security for metadata access
Measurements to gauge the quality and usability of
metadata
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Information about data is referred to as Metadata.
DBA’s rely on metadata to manage a database.
 In order for data to be anything more than simply
data, metadata is required.
 Metadata strategy
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TYPE OF METADATA
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SSN is 9 digits of numbers
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ANI is 10 digit of numbers starting with not 0 or 1
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Technology metadata – technical aspects of the data
as it relates to storing and managing the data in
computerized systems
Business metadata – aspects of how the data is used
by the business, and is needed for the data to have
value to the organization
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SSN is a unique identification number, associated with a person
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ANI’s first 3-digits are area code, and the remaining 7 digits are local phone
number.
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DBMS METADATA
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For DBA’s, the DBMS itself is a good source of
metadata
 System catalog – technology metadata about
database objects
Names of every database, table, column, index, view,
relationship
 Constraints such as primary key, foreign key, and not null
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System catalog is
Active – automatically build and maintained
 Integrated – the system catalog is a part of DBMS and up-todate with any changes within the database
 Non-subvertible – DMBS operations are the only mechanism
for populating the system catalog
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REPOSITORY
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A repository stores information about an
organization’s data assets.
 Repository is used for
Store information about your data, processes, and environment.
 Support multiple ways of looking at the same data
 Store in-depth documentation, and produce detail and management
reports
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Repository benefits
Integrated views of multiple systems
 The consistency it provides in documenting data elements and business
rules
 Support of a rapidly changing environment
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Repository challenges
Keeping the repository up-to-date
 Many metadata sources, such as application component metadata,
business metadata, data modeling metadata, database metadata
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ITEC 450
MODULE 5 Metadata, Tools,
and Data Warehousing
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Section 2 Database Management Tools
BENEFITS OF DATABASE MANAGEMENT
TOOLS
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A DBA tool reduces the amount of time, effort, and
human error involved in maintaining efficient
database systems and applications.
 Ease the administrative burdens
 Fulfill market niches not adequately supported by
the major DBMS vendors
 Automate database monitoring and routine
activities
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DATA MODELING AND DESIGN TOOLS
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The tools provide a consistent and coherent means of
creating conceptual and logical data models and
transforming them into physical database designs.
 Do not have to be unique to a specific database
 Support the standard tasks associated with logical data
modeling such as entity-relationship diagramming and
normalization
 Create a physical data model geared to each of your
target DBMS platforms
 Reverse engineering to generate standard DDL
automatically from major DBMS system catalog
 Examples: Erwin from CA, PowerDesigner from Sybase,
ER/Studio from Embarcadero, Rational Data Architect
from IBM, MySQL workbench from MySQL, Oracle
Designer from Oracle
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CHANGE MANAGEMENT TOOLS
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The tools provide capabilities to perform various
database alterations.
 Alter database parameters that can not be easily
performed with ALTER statement
 Modify database structures with cascading effects
 Change a column’s data type and length
 Remove columns from a table
 Batch requested changes into a work list that can
be executing in the foreground or the background
 Provide database analysis and planning prior to
implementing database changes
 Examples: CA Database Command Center
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DATABASE COMPARISON TOOLS
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The tools enable DBA’s to compare one database to
another in terms of its database objects and
structures. Such tools will identify differences and
automatically generate the DDL to sync among
databases.
 Find missing migrations
 Detect any discrepancies among different databases
 Are often useful during application program testing
and debugging
 Examples: TOAD from Quest, SQL Compare for
SQL Server from Red Gate
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DATABASE OBJECT MIGRATION TOOLS
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The tools facilitate the quick migration of database
objects from one environment to another.
 Provide a systematic method to promote changes
instead of manually running DDL’s
 Can migrate all dependent objects and security
 Enhance database securities
 Reduce the migration time
 Examples: Softek LDMF from IBM, DBMigration
from shareware
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PERFORMANCE MANAGEMENT TOOLS
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System Performance Tools
Examine the database server, its configuration, and usage
 Monitor and report CPU, Memory, I/O usage and history info
 Trace individual process and capture information
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Database Performance Tools
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Read the database statistics from the system catalog, and provide
additional analysis with enhanced tool capability
Set thresholds and provide maintenance actions
Provide a series of canned reports detailing the potential
problems
SQL Performance Tools
Analyze the SQL in an application program
 Suggest alternative SQL solutions
 Assess impacts caused by database object changes
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EVALUATING DBA TOOL VENDORS
List of features
 Vendor reputation
 Customer satisfaction
 Support model and enhancement request
 Upgrade and new feature development/support
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ITEC 450
MODULE 5 Metadata, Tools,
and Data Warehousing
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Section 3 Oracle Data Dictionary and Dynamic
Performance Views
ORACLE DATA DICTIONARY
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It’s the heart of the DBMS, and key to DBA’s success.
The views are static, as Oracle updates them only when a
DDL transaction take place.
 The underline tables are located in the SYSTEM
tablespace, and owned by the user SYS. The data
dictionary views are built on top of these base tables.
 The data dictionary contains key items:
User information, roles and privileges
 Object information, constraint information, storage information
 Storage information, operational information
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The three sets of data dictionary views with prefix of:
USER – objects that the user owns
 ALL – objects that the user has been granted privileges
 DBA – all objects in the database, accessible by DBA’s or special granted
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GENERAL VIEWS
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DICT – all data dictionary views and short
description
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PRODUCT_COMPONENT_VERSION – version of
all major components of the Oracle database
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SQL> select * from DICT where table_name like '%INDEXES';
SQL> select * from product_component_version;
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DBA_SOURCE – source code of a database object
SQL> select text from dba_source where owner = 'HR' and name =
'SECURE_EMPLOYEES';
SQL> select text from dba_source where owner = 'HR' and name =
'SECURE_DML';
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DBA_OBJECTS– all objects in the database
SQL> select object_name, object_type from dba_objects where
owner = ‘HR’;
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USER MANAGEMENT RELATED VIEWS
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DBA_USERS – database user info
SQL> select username, account_status from dba_users;
DBA_ROLES – all database roles
SQL> select * from dba_roles;
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DBA_SYS_PRIVS, DBA_ROLE_PRIVS – System
and role privileges
 DBA_TAB_PRIVS – table-level privielges
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SQL> select grantee, privilege from dba_tab_privs
where owner = 'HR' and table_name = 'EMPLOYEES';
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STORAGE RELATED VIEWS
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DBA_FREE_SPACE – free space of tablespace
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DBA_SEGMENTS – segment details
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SQL> select tablespace_name, sum(bytes) from dba_free_space
group by tablespace_name;
SQL> select segment_name, segment_type, tablespace_name
from dba_segments where owner = 'HR';
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DYNAMIC PERFORMANCE VIEWS
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The views are dynamic, as they are updated
continuously while the database is running. Also
called v$ views.
 Memory related views
 Session and user related views
 Performance-monitoring views
 SQL-related views
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COMMONLY USED VIEWS
Memory – v$sga, v$sgastat
 Session – v$session, v$sess_io, v$session_longops
 SQL info – v$sql, v$sqltext
 Performance – v$instance, v$lock, v$locked_object
 General – v$instance, v$license, v$database,
v$parameter
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