Technical Interview Questions
2NF is the Second Normal Form. A table is said to be 2NF if it follows the following conditions: The table is in 1NF, i.e., firstly it is necessary that the table should follow the rules of 1NF. Every non-prime attribute is fully functionally dependent on the primary key, i.e., every non-key attribute should be … Read more
1NF is the First Normal Form. It is the simplest type of normalization that you can implement in a database. The primary objectives of 1NF are to: Every column must have atomic (single value) To Remove duplicate columns from the same table Create separate tables for each group of related data and identify each row … Read more
he Join operation is one of the most useful activities in relational algebra. It is most commonly used way to combine information from two or more relations. A Join is always performed on the basis of the same or related column. Most complex queries of SQL involve JOIN command. There are following types of join: … Read more
Following are three levels of data abstraction: Physical level: It is the lowest level of abstraction. It describes how data are stored. Logical level: It is the next higher level of abstraction. It describes what data are stored in the database and what relationship among those data. View level: It is the highest level of … Read more
Data independence specifies that “the application is independent of the storage structure and access strategy of data.” It makes you able to modify the schema definition at one level without altering the schema definition in the next higher level. It makes you able to modify the schema definition in one level should not affect the … Read more