What is Data?

In simple words, data can be facts related to any object in consideration. For example, your name, age, height, weight, etc. are some data related to you. A picture, image, file, pdf, etc. can also be considered data.

What is a Database?

A database is a systematic collection of data. They support electronic storage and manipulation of data. Databases make data management easy.

Let us discuss a database example: An online telephone directory uses a database to store data of people, phone numbers, and other contact details. Your electricity service provider uses a database to manage billing, client-related issues, handle fault data, etc.

Let us also consider Facebook. It needs to store, manipulate, and present data related to members, their friends, member activities, messages, advertisements, and a lot more. We can provide a countless number of examples for the usage of databases.

In computing, a database is an organized collection of data stored and accessed electronically from a computer system. Where databases are more complex they are often developed using formal design and modeling techniques

Types of Databases

Here are some popular types of databases.

Distributed databases:

A distributed database is a type of database that has contributions from the common database and information captured by local computers. In this type of database system, the data is not in one place and is distributed at various organizations.

Relational databases:

This type of database defines database relationships in the form of tables. It is also called Relational DBMS, which is the most popular DBMS type in the market. Database example of the RDBMS system include MySQL, Oracle, and Microsoft SQL Server database.

Object-oriented databases:

This type of computers database supports the storage of all data types. The data is stored in the form of objects. The objects to be held in the database have attributes and methods that define what to do with the data. PostgreSQL is an example of an object-oriented relational DBMS.

Centralized database:

It is a centralized location, and users from different backgrounds can access this data. This type of computers databases store application procedures that help users access the data even from a remote location.

Open-source databases:

This kind of database stored information related to operations. It is mainly used in the field of marketing, employee relations, customer service, of databases.

Cloud databases:

A cloud database is a database which is optimized or built for such a virtualized environment. There are so many advantages of a cloud database, some of which can pay for storage capacity and bandwidth. It also offers scalability on-demand, along with high availability.

Data warehouses:

Data Warehouse is to facilitate a single version of truth for a company for decision making and forecasting. A Data warehouse is an information system that contains historical and commutative data from single or multiple sources. Data Warehouse concept simplifies the reporting and analysis process of the organization.

NoSQL databases:

NoSQL database is used for large sets of distributed data. There are a few big data performance problems that are effectively handled by relational databases. This type of computers database is very efficient in analyzing large-size unstructured data.

Graph databases:

A graph-oriented database uses graph theory to store, map, and query relationships. These kinds of computers databases are mostly used for analyzing interconnections. For example, an organization can use a graph database to mine data about customers from social media.

OLTP databases:

OLTP another database type which able to perform fast query processing and maintaining data integrity in multi-access environments.

Personal database:

A personal database is used to store data stored on personal computers that are smaller and easily manageable. The data is mostly used by the same department of the company and is accessed by a small group of people.

Multimodal database:

The multimodal database is a type of data processing platform that supports multiple data models that define how the certain knowledge and information in a database should be organized and arranged.

Document/JSON database:

In a document-oriented database, the data is kept in document collections, usually using the XML, JSON, BSON formats. One record can store as much data as you want, in any data type (or types) you prefer.

What is database administration?

Database administration is the function of managing and maintaining database management systems software. Mainstream DBMS software such as Oracle, IBM DB2 and Microsoft SQL Server need ongoing management

Database administration refers to the whole set of activities performed by a database administrator to ensure that a database is always available as needed. Other closely related tasks and roles are database security, database monitoring and troubleshooting, and planning for future growth.

Database administration is an important function in any organization that is dependent on one or more databases.

The database administration (DBA) is usually a dedicated role in the IT department for large organizations. However, many smaller companies that cannot afford a full-time DBA usually outsource or contract the role to a specialized vendor, or merge the role with another in the ICT department so that both are performed by one person.

The primary role of database administration is to ensure maximum up time for the database so that it is always available when needed. This will typically involve proactive periodic monitoring and troubleshooting. This in turn entails some technical skills on the part of the DBA. In addition to in-depth knowledge of the database in question, the DBA will also need knowledge and perhaps training in the platform (database engine and operating system) on which the database runs.

A DBA is typically also responsible for other secondary, but still critically important, tasks and roles. Some of these include:

• Database Security: Ensuring that only authorized users have access to the database and fortifying it against any external, unauthorized access.
• Database Tuning: Tweaking any of several parameters to optimize performance, such as server memory allocation, file fragmentation and disk usage.
• Backup and Recovery: It is a DBA’s role to ensure that the database has adequate backup and recovery procedures in place to recover from any accidental or deliberate loss of data.
• Producing Reports from Queries: DBAs are frequently called upon to generate reports by writing queries, which are then run against the database.

It is clear from all the above that the database administration function requires technical training and years of experience. Some companies that offer commercial database products, such as Oracle DB and Microsoft’s SQL Server, also offer certifications for their specific products. These industry certifications, such as Oracle Certified Professional (OCP) and Microsoft Certified Database Administrator (MCDBA), go a long way toward assuring organizations that a DBA is indeed thoroughly trained on the product in question. Because most relational database products today use the SQL language, knowledge of SQL commands and syntax is also a valuable asset for today’s DBAs.

What are the functions of a database administrator?

1. Selection of hardware and software

• Keep up with current technological trends
• Predict future changes
• Emphasis on established off the shelf products

2. Managing data security and privacy

• Protection of data against accidental or intentional loss, destruction, or misuse
• Firewalls
• Establishment of user privileges
• Complicated by use of distributed systems such as internet access and client/ server technology.

How many major threats to database security can you think of?

1. Accidental loss due to human error or software/ hardware error.
2. Theft and fraud that could come from hackers or disgruntled employees.
3. Improper data access to personal or confidential data.
4. Loss of data integrity.
5. Loss of data availability through sabotage, a virus, or a worm.

3. Managing Data Integrity

• Integrity controls protects data from unauthorized use
• Data consistency
• Maintaining data relationship
• Domains- sets allowable values
• Assertions- enforce database conditions

4. Data backup

• We must assume that a database will eventually fail
• Establishment procedures
  • how often should the data be back-up?
  • what data should be backed up more frequently?
  • who is responsible for the back ups?
• Back up facilities
  • automatic dump- facility that produces backup copy of the entire database
  • periodic backup- done on periodic basis such as nightly or weekly
  • cold backup- database is shut down during backup
  • hot backup- a selected portion of the database is shut down and backed up at a given time
  • backups stored in a secure, off-site location

5. Database recovery

• Application of proven strategies for reinstallation of database after crash
• Recovery facilities include backup, journalizing, checkpoint, and recovery manager

If there are back up facilities, are there also journalizing, checkpoint, and recovery facilities?

Yes

• Journalizing facilities include:
  • audit trail of transactions and database updates                   
  • transaction log which records essential data for each transaction processed against the database
  • database change log shows images of updated data.  The log stores a copy of the image before and after  modification.
• Checkpoint facilities:
  • when the DBMS refuses to accept a new transaction, the system is in a quiet state
  • database and transactions are synchronized
  • allows the recovery manager to resume processing from a short period instead of repeating the entire day
• Recovery and Restart Procedures
  • switch- mirrored databases
  • restore/rerun– reprocess transactions against the backup
  • transaction integrity- commit or abort all transaction changes l

6. Tuning database performance

• Set installation parameters/ upgrade DBMS
• Monitor memory and CPU usage
• Input/ output contention
  • user striping
  • distribution of heavily accessed files
• Application tuning by modifying SQL code in applications

lll

7. Improving query processing performance ll

Are there any shared administration functions?

Yes

These are share administration functions

 1. Database design

• DA is responsible for logical design
• DBA is responsible for the external model design (subschemas), the physical design (construction), and for designing integrity controls

2. Database implementation

• DBA
  • establish security controls
  • supervise database loading
  • specify test procedures
  • develop programming standards
  • establish back up/ recovery procedures
• Both
  • specify access policies
  • user training

3. Operations and maintenance

• DBA
  • monitor database performance
  • tune and reorganize databases as needed
  • enforce standards and procedures
• Both
  • support users

4. Growth and change

• Both
  • implement change-control procedures
  • plan for growth and change
  • evaluate new technologies

New functions

1. Data warehouse administration

• New function due to the increase use of data warehousing
  • (massively) integrated decision support databases from various sources
• Emphasis on integration and coordination of data and metadata from multiple databases
• Specific functions
  • support decision-oriented applications
  • manage data warehouse (exponential) growth
  • establish service level agreements

Advantages and Disadvantages of Database Management System(DBMS)

Advantages of Database Management System (DBMS)

1. Improved data sharing

An advantage of the database management approach is, the DBMS helps to create an environment in which end users have better access to more and better-managed data.

Such access makes it possible for end users to respond quickly to changes in their environment.

2. Improved data security

The more users access the data, the greater the risks of data security breaches. Corporations invest considerable amounts of time, effort, and money to ensure that corporate data are used properly. A DBMS provides a framework for better enforcement of data privacy and security policies.
 

3. Better data integration

Wider access to well-managed data promotes an integrated view of the organization’s operations and a clearer view of the big picture. It becomes much easier to see how actions in one segment of the company affect other segments.

4. Minimized data inconsistency

Data inconsistency exists when different versions of the same data appear in different places. For example, data inconsistency exists when a company’s sales department stores a sales representative’s name as “Bill Brown” and the company’s personnel department stores that same person’s name as “William G. Brown,” or when the company’s regional sales office shows the price of a product as $45.95 and its national sales office shows the same product’s price as $43.95. The probability of data inconsistency is greatly reduced in a properly designed database.

 5. Improved data access

 The DBMS makes it possible to produce quick answers to ad hoc queries. From a database perspective, a query is a specific request issued to the DBMS for data manipulation—for example, to read or update the data. Simply put, a query is a question, and an ad hoc query is a spur-of-the-moment question. The DBMS sends back an answer (called the query result set) to the application. For example, end users, when dealing with large amounts of sales data, might want quick answers to questions (ad hoc queries) such as:

– What was the dollar volume of sales by product during the past six months?
– What is the sales bonus figure for each of our salespeople during the past three months?
– How many of our customers have credit balances of 3,000 or more?

6. Improved decision making

Better-managed data and improved data access make it possible to generate better-quality information, on which better decisions are based. The quality of the information generated depends on the quality of the underlying data. Data quality is a comprehensive approach to promoting the accuracy, validity, and timeliness of the data. While the DBMS does not guarantee data quality, it provides a framework to facilitate data quality initiatives.

7. Increased end-user productivity

The availability of data, combined with the tools that transform data into usable information, empowers end users to make quick, informed decisions that can make the difference between success and failure in the global economy.

Till now we have seen different benefits of database management systems. But it has certain limitations or disadvantages.

Let’s find various disadvantages of database system. 

Disadvantages of Database Management System (DBMS):

 Although the database system yields considerable advantages over previous data management approaches, database systems do carry significant disadvantages. For example:

1. Increased costs

one of the disadvantages of dbms is Database systems require sophisticated hardware and software and highly skilled personnel. The cost of maintaining the hardware, software, and personnel required to operate and manage a database system can be substantial. Training, licensing, and regulation compliance costs are often overlooked when database systems are implemented.

2. Management complexity

Database systems interface with many different technologies and have a significant impact on a company’s resources and culture. The changes introduced by the adoption of a database system must be properly managed to ensure that they help advance the company’s objectives. Given the fact that database systems hold crucial company data that are accessed from multiple sources, security issues must be assessed constantly.

3. Maintaining currency

To maximize the efficiency of the database system, you must keep your system current. Therefore, you must perform frequent updates and apply the latest patches and security measures to all components.

Because database technology advances rapidly, personnel training costs tend to be significant. Vendor dependence. Given the heavy investment in technology and personnel training, companies might be reluctant to change database vendors.

As a consequence, vendors are less likely to offer pricing point advantages to existing customers, and those customers might be limited in their choice of database system components.

4. Frequent upgrade/replacement cycles

DBMS vendors frequently upgrade their products by adding new functionality. Such new features often come bundled in new upgrade versions of the software. Some of these versions require hardware upgrades. Not only do the upgrades themselves cost money, but it also costs money to train database users and administrators to properly use and manage the new features.

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