Wk-04

Components of DBMS Environment • 2. 3. 4. 5. 6.

There are five major components in the DBMS environment Hardware Software Data Procedures People

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Components of DBMS Environment •

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Hardware : The DBMS and the application require hardware to run. The hardware can range from a single personal computer, to a single mainframe, to a network of computers. The particular hardware depends on the organization’s requirements and the DBMS used. Software: The software component consist the DBMS software itself and the application programs, together with the operating system, including network software if DBMS is being used over a network.

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Components of DBMS Environment •

Typically, application programs are written in a thirdgeneration programming language(3GL) such as ‘C’, C++,java, visual Basic, COBOL, Fortran, or Pascal or using a fourth-generation language (4GL) such as SQL.

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Data: The most important component of the DBMS environment is the data. As we observe that the data acts as a bridge between the machine components and the human components. The database contains both the operational data and the meta-data.

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Components of DBMS Environment •

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Procedures: procedures refer to the instructions and rules that govern the design and use of the database. The user of the system that manage the database require documented procedures on how to use or run the system. These may consist of instructions on how to: log on to the DBMS Use a particular facility Start and stop the DBMS Make backup copies of the database Handle H/W and S/W failures PRESENTED BY S.HAYAT

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Components of DBMS Environment • People: The final component is the people involved with the system.

• H/w---S/w

Machine

Data Procedures---People

Bridge

Human

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Database Administrator

• The database and the DBMS are corporate resources that must be managed like any other resource and that resource body is the Database Administrator. • Database Administrator is responsible for the physical realization of the database application, including physical database design, implementation,security and integrity control, maintenance of the operational system and ensuring satisfactory performance of the applications for users. PRESENTED BY S.HAYAT

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Database Administrator • • • • • • • •

MAJOR TASKS OF THE DBA Evaluating and selecting DBMS products Undertaking physical database design Defining security and integrity constraints To work closely with database developers Developing test strategies Training to users Responsible for “signing off ”the implemented database application.

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Database Administrator • Monitoring system performance and tuning the database as appropriate • Performing backups routinely • Ensuring recovery mechanism and procedures • Keeping up to date with software and hardware developments and costs, installing updates as necessary

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Database System

• “Shared collection of logically related data and a description of this data ,design to meet the information needs of an organization”

• “An Organized collection of logically related data, usually designed to meet the information needs of multiple users in an organization”.

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Database System • The database holds not only the organization’s operational data but also a description of this data. •

If a database is developed for Students, it will contain data about the Student i.e. Roll no, Name ,Father Name , Class, Department , Session, Address, Contact# etc

• All data are stored in form of tables in Database.

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Database System • Tables/Relations. • Tables is the fundamental object the database structure.The basic aim of tables is to stored data • Tables consists Rows and columns(Fig shows)

Roll no 1 2

Name Ali Zain

Class Bcs Bcs

Address pesh kohat

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Cntct 12345 67654

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Database System • Rows / Records / Tuple • Row is the horizontal part of the table, It is the collection of related fields

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Ali

Bcs

pesh

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12345

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Database System • Column / Field. • Columns are the vertical part of the table.

Name Ali zain

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Database System Components of the Database Environment • CASE Tools – computer-aided software engineering • Repository – centralized storehouse of metadata • Database Management System (DBMS) – software for managing the database • Database – storehouse of the data • Application Programs – software using the data

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Database System • User Interface – text and graphical displays to users • Data Administrators – personnel responsible for maintaining the database • System Developers – personnel responsible for designing databases and software • End Users – people who use the applications and databases

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Components of the database environment

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DBMS • “ A software system that enables users to define , create, maintain and control access to the database” • The DBMS is the s/w that interacts with the users , application programs and the database. • DBMS is the general purpose s/w system that provides the following facilities

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DBMS 1.

DBMS provides the facility to define the structure of database. The user can specify data types, formats and constraints.

3.

DBMS provide the facility to contain data( operational data, metadata) on some storage device controlled by DBMS.

5.

That s/w provide the facility to insert, delete, update and retrieve specific data, to generate reports etc.

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DBMS Application #1

Application #2

Application #3

DBMS

Database containing centralized shared data

DBMS manages data resources like an operating system manages hardware resources PRESENTED BY S.HAYAT

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Application Programmer • Once the database has been implemented the application programs that provide the required functionality for the end-user’s must be implemented and this is the responsibility of the application programmer. • So we can say that the application programmer is a professional who writes computer programs in high level languages such as 3GL and 4GL. • Typically the application programmer work from a specification produced by system analysts.

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Application Programmer • Each program contain statements that requests the DBMS to perform some operation on the database include retrieving data, inserting, updating and deleting data.

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User • The end-users are the ‘clients’ for the database, which has been designed and implemented, and is being maintained to serve their information needs. • End-users can be classified according to the way they use the system.  Naïve users: are typically unaware of the DBMS. • They access the database trough specially written application programs which attempt to make the operation as simple as possible.

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User • They invoke database operations by entering simple commands or choosing options from a menu .  Sophisticated users: this type of end-user is familiar with the structure of the database and the facilities offered by the DBMS. Sophisticated end-users may use a high-level query language such as SQL to perform the required operations

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Data Dictionary & Directory/Repositories Data Dictionary: “a repository of information about a database that documents data elements of a database” It is an integral part of the relational DBMS’s, which stores metadata or information about the database. Including attributes names & definitions for each tables in database

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Data Dictionary & Directory/Repositories

• Data dictionary is the part of the system catalog. Where system catalog describes all database objects including tables related data, such as tables names, column names, data types, foreign keys & primary keys, authorized users, users access privileges & so on.

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Data Dictionary & Directory/Repositories

• System catalog is created by DBMS & the information stored in system tables. • Data dictionaries may either active or passive.

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Data Dictionary & Directory/Repositories • Active & Passive Dictionaries. • Active Dictionary • Active data dictionary automatically managed by the BDMS. • Active system are always related with the current structure and definition of the database.

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Data Dictionary & Directory/Repositories • Most of RDBMS contain active dictionary that can be derived from their system catalog. • Passive Dictionary. • This type of dictionary is managed by the user’s of the system, & modified whenever structured of the database is changed. • However the passive data dictionary may be maintained as a separate database. PRESENTED BY S.HAYAT

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Data Dictionary & Directory/Repositories • Passive data dictionary are not limited to information that can be discerned by the DBMS.

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Data Dictionary & Directory/Repositories • Information Repository “a component that stores metadata which describes an organization’s data and data processing resources, manages the total information environment, and combines information about an organization’s business information and its application portfolio”

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Data Dictionary & Directory/Repositories • Information repositories are used by data administrators and other specialists to manage the total information processing environment.

• The information repositories are the essential components of both the development and production environment.

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Data Dictionary & Directory/Repositories • Information Repository Dictionary System (IRDS) “ a computer software tool that is used to manage and control access to the information repository” • It provide facilities for recording , storing, and processing descriptions of an organization’s significant data and data processing resources

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Data Dictionary & Directory/Repositories •

Repository engine supports five major functions.

3. 4. 5. 6. 7.

Object management Relationship management Dynamic extensibility Version management Configuration management

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