Database Interview Questions

Database Interview Questions

They were designed to store information related to multimedia, spatial and engineering databases. Some of the databases even stored data about software?s repositories. This was adopted in late ninety?s and new features were added.

1. Explain about the database management systems?

Database management systems use specialized software to store the database, make necessary changes, securing the database, etc. These DBMS are categorized according to the work they do. Much of the DBMS and its applications are primarily not designed for data they are designed for concurrency, performance, integrity, and failure troubleshooting.

2. Explain about the hierarchical model of database?

If you can imagine a tree with branches then you know to work with this database. It has a downward link to describe the nesting and they are arranged in a particular order down the same level of the list. With this database model you can form a logical relationship among different types of data

3) Explain about object oriented databases?

Object oriented databases are used to store much more complex data.
They were designed to store information related to multimedia, spatial and engineering databases. Some of the databases even stored data about software?s repositories. This was adopted in late ninety?s and new features were added.

4. Explain about Network model?

Network is complex, time consuming and costly. This model of storing database has many parents and finding a logical relationship between them is extremely difficult. This model provides greater flexibility and easy access to data. Navigating through links is a easy way to search for data.

5. Explain about the process of user request and data generating?

Users request information and this request is transformed into a special language usually that would be the dialect in sql. This dialect would be given to the appropriate software for culminating the database for appropriate presentation to the end user. Usually sql queries are increasingly being embedded into software.

6. Explain the role of indexing in databases?

Many of the databases take advantage of indexing to increase the speed. This technology has increased immensely since it?s inception stages. During indexing if a row matches the query it is automatically generated and given to the user. In RDBMS indexes can be created and dropped without changing the existing application.

7. Explain about post relational databases?

Post relational databases are similar to relational database management systems but they have pre dated relational model of data representation. This model doesn`t require representation of data with relationship. A perfect example can be a tree with nodes represented in a directed graph.

8. Explain about normal forms?

Databases are categorized into different forms based upon the anomalies to which they are vulnerable. Lowest rung of database is known as normal form of first order. A first order normal form is subjected to many types of vulnerabilities. A higher database cannot be subjected to any vulnerability. You can get more info about Databases at Database Guides.

9) Explain about primary key?

A primary holds a unique key for each row designated in the table. Keys are often used to combine more than two tables, columns, or rows. Keys should be defined in advance before and it will be too late to define them later.

10. What are the three basic rules which are to be followed for relational model of database?

There are three basic rules to follow for relational database they are
1) It least bothers about order of the columns
2) No clones or identical rows allowed.
3) Each and every row will have a value for each column.

11. Explain about XML databases?

XML databases came into existence in 2000. Many of the new startups were also started. This database lets you organize data irrespective of whether it is organized or not. Arranging and complexity for storing data is significantly got reduced with the language.

12. Explain about what a database is?

Database is an important constituent for collection and storage of data. A computer database uses software for managing its huge pool of database. It also uses software to make changes automatically to the database without any outside interference.

13) Explain about relational database management systems?

Relational database systems take the model and form of relational model. Data is represented in the form of columns and rows which are later represented by relation operators. Explicit pointers will not interfere between tables.

14) State the ACID rules?

Some of the acid rules stated are described as follows.
1) Atomicity: -Either transaction should be done or they should be stopped
2) Consistency: – Data should never be in a contradictory state
3) Isolation: – Two simultaneous or preceding results should never interfere with each other.
4) Durability: -Results or Data shouldn?t be discarded even during a crash of the system.

15) Explain about the Storage and physical database design?

Databases can be stored in many forms. They are usually stored on hard disks in many different forms in the form of flat files, hash buckets, ISAM, etc. Data can be stores by partitioning the data. Normalization and de normalization is generally used for efficient storage of database and also for memory management.