Database Management System: The Responsibilities of a Dba

Software installation and Maintenance

A DBA often collaborates on initial installation and configuration of a new database. DBA installs the “Database software” and configures it for use. As updates and patches are required, the DBA handles the on-going maintenance. Once there is a new server the DBA handles the transfer of data from the old server to the new platform

Data Extraction, Transformation, and Loading

This is known as ETL (Data Extraction, Transformation, And Loading) this refers to the efficiently important large volume of data which come from extracting multiple systems data into a data warehouse environment. This external data has been cleaned up and transformed to fit the desired format so that it can be imported to a central repository.

Security

A DBA needs to know the potential weaknesses of the database software and the company’s whole system and to minimize the risk of the database software. There isn’t a single system that is one hundred percent immune to attacks, but the risk can be minimize to the lowest.

Backup and Recovery

DBAs creates backup and recovery plans and procedures based on the industry best practices, then make sure all steps has been followed. Backups cost a lot of time and money so the DBA may have to manage to take necessary precautions to preserve data.

The Advantage of a database management system:

A database management system(DBMS) is an application software that allows user to define, create and manager/maintain a database while providing the ability to maintain multiple access control and security of the data stored.

Controlling Data Redundancy:

With a DBMS it allows you to control data redundancy, this means in a non-database system each application program has its own private files. This means a duplicated copies of the same data are created in many places. But in the other hand with a DBMS all data of an organization is integrated into a single database file, and this means that the data is recorded in only one place in the database and it is not duplicated at multiple places.

Sharing of Data:

In a DBMs data can also be shared by authorized users of the organization. This means that the database administrator manages the data and give rights to users that are allow to access the data and this allows multiple user to access the same piece of the information simultaneously. And the data of the same database can be shared between different applications programs.

Data Consistency:

Data consistency is obtained by controlling data redundancy. For example, if a data appears only once, any update done to it has to be performed only once and the update is immediately available to all users. The database system enforces consistency when the DBMA has controlled redundancy.

Integration of Data:

Data in a database are stored in table forms in a DBMS. So in a single database it contains multiple tables and then this enables relationships to be created between tables. This can make it easier to retrieve and update data.

Integration Constraints:

DBMS allows us to apply integration constraints to database so that it ensure the data that has been entered to the database is correct. The constraints may be applied to data item within a single record or to a relationship between records.

Data Security:

The forms are very important object of a DBMS. To create a form is very easy and quickly and it provides very easy ways to enter data into database, edit, and display the data from database. So that non-technical users can also perform operations on database with the form without going into technical details. So Data security is important.

Report Writers:

In most of the DBMSs there will be a report writer, this tool is used to create reports. this can be created very easily by the user. The create report are also save along with database and it behaves like a software component

Control Over Concurrency:

With a file base system when 2 users are simultaneously accessing the data it is possible that they will interfere with each other. So most Database Management system have sub-system to control the concurrency so that all transaction are always recorded with currency, this means that users that are accessing data simultaneously won’t interfere each other.

Backup and Recovery Procedures:

The user can create the backup of data to protect all the valuable data from damaging due to fails to computer system or application programs. And it will take very long to back up large amount of data with a file-based system. So most of the DBMS provide a sub-system that will create the backup of data and restore the data automatically if required.

Data Independence:

In a DBMS the user can change the structure of database without modifying the application program this is call data independence.

Categories of database models:

Relational model:

The Relational model also known as RM for database management is a leading to managing data using a structure and language consistent. This model sorts data into tables, also known as relations, each of the table consists of columns and rows and each column lists an attribute of the entity

Object model:

An object database is a database management system in which the information is represented in for of object known as object-oriented programming. This model defines database as a collection of objects or reusable software element. For example, a multimedia database is an object database due to that it contains medias such as images.

XML model:

This is data persistence software system which enables data to be specified properly, and sometimes stored in format of XML. This data can be queried, transformed, exported and then returned to a system that requires the data.

What is the difference between a database schema and a database state?

1. When a new database has been created we specify that it’s a database schema (only to the DBMS).
2. When the database is first loaded with initial data it’s an initial state of the database
3. Database state can also refer to update operation has been done to the database.
4. The DBMS is also responsible to ensure that the state of the database is a valid state-that is, which means the state that satisfies the structure and constraints specified in to the schema.

So overall Database schema is the design of the database. It’s a mind map that represents the logical view of the whole database and it tells how the data is organized. And database state is the content of the database at a moment in time.

UML Notation for Entity Relationship Models:

UML (unified Modeling Language) this method is use for specifying, visualizing, and documenting all the artifacts or an object-oriented system that’s under development. UML is a combined of Booch, Objectory, and OMT.