File Name: databases interview questions and answers .zip
What is a DBMS? A DBMS receives requests from applications and translates those requests into actions on a specific database.
- Top 50 Database(DBMS) Interview Questions & Answers
- Top 50+ Database Interview Questions and Answers
- Top 50 DBMS Interview Questions You Need to know
A prearranged collection of figures known as data is called database.
Top 50 Database(DBMS) Interview Questions & Answers
Watch our Demo Courses and Videos. Answer: Name. Every relation in a relational database should have a name which is unique among all other relations. Each column in a relation is called an attribute.
Each and every row in a relation is called a tuple. A tuple defines a collection of attribute values. Answer: E-R model is an Entity-Relationship model. E-R model is based on a real-world which is made up of entities and related objects. Entities are illustrated in a database by a set of attributes. Answer: The object-oriented model is based on collections of objects. An object accommodates values which are stored in instance variables inside the object.
Objects having an identical type of values and the exact same methods are grouped together into classes. Answer: 1. Physical level: This is the lowest level of abstraction and it describes how data is stored.
Logical level: The next level of abstraction is logical, it describes what type of data is stored in a database and what is the relationship between these data. View level: The highest level of abstraction and it describes the only entire database. Rule 1: The information rule: Each and every information in the database is to be represented uniquely, mainly name values in column positions within a different row of a table.
Rule 2: The guaranteed access rule: All data must be ingressive. Rule 5: The comprehensive data sublanguage: The system has to assist a minimum of one relational language that: 1. Has a linear syntax 2. Which can be used as both interactively and within application programs, 3. It supports data definition operations DDL , data manipulation operations DML , security and integrity constraints, and transaction management operations begin, commit, and rollback.
Rule 6: The view updating rule: All views that theoretically improve must be upgradable by the system. Rule 7: High-level insert, update, and delete: The system must support insert, update, and delete operators. Rule 8: Physical data independence: Modify the physical level how the data is stored, using arrays or linked lists etc. Rule 9: Logical data independence: Modify the logical level tables, columns, rows etc. Rule Integrity independence: Integrity constraints must be identified individually from application programs and stored in the catalog.
Rule Distribution independence: The distribution of portions of a database to different locations should not be visible to users of the database.
Rule The nonsubversion rule: If the system provides a low-level i. Answer: Database normalization is a process of organizing data to minimize data redundancy. Which in turn ensures data consistency. There are many problems associated with data redundancy such as disk space wastage, data inconsistency, DML Data Manipulation Language queries become slow.
The table does not contain any repeating column groups. Identity each record uniquely using the primary key. Moreover, it creates a relationship between these tables using foreign keys. A primary key can be defined at column level or table level. Only one primary key per table is allowed. Foreign key: foreign key allows the values present in the referenced column only.
It allows duplicate or null values. It can be defined as a column level or table level. Candidate Key: A Candidate key is minimum super key, there is no proper subgroup of Candidate key attributes can be a super key. Super Key: A superkey is a set of attributes of a relation schema on which all attributes of the schema are partially dependent. No two rows can have the same value of super key attributes.
Answer: Indexes are: — Clustered index: — It is the index at which data is physically stored in the disk. Therefore, only one clustered index can be created to a database table.
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Top 50+ Database Interview Questions and Answers
What is BCP? When is it used? Answer: It is a tool used to duplicate an enormous quantity of information from tables and views. It does not facsimile the structures the same as a foundation to target. Explain the steps needed to create a scheduled job? Right-click on jobs and choose Add New.
What are advantages of DBMS over traditional file based systems? Ans: Database management systems were developed to handle the following difficulties of typical Fille-processing systems supported by conventional operating systems. Data redundancy and inconsistency 2. Difficulty in accessing data 3. Data isolation — multiple files and formats 4. Integrity problems 5. Atomicity of updates 6.
Watch our Demo Courses and Videos. Answer: Name. Every relation in a relational database should have a name which is unique among all other relations. Each column in a relation is called an attribute. Each and every row in a relation is called a tuple. A tuple defines a collection of attribute values. Answer: E-R model is an Entity-Relationship model.
Top 50 DBMS Interview Questions You Need to know
DBMS is a collection of programs that facilitates users to create and maintain a database. In other words, DBMS provides us an interface or tool for performing different operations such as the creation of a database, inserting data into it, deleting data from it, updating the data, etc. DBMS is a software in which data is stored in a more secure way as compared to the file-based system. Using DBMS, we can overcome many problems such as- data redundancy, data inconsistency, easy access, more organized and understandable, and so on.
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