SSC CGL Exam > SSC CGL Videos > SSC CGL Tier 2 - Study Material, Online Tests, Previous Year > Constraints and Database Schemas
Constraints and Database Schemas Video Lecture | SSC CGL Tier 2 - Study Material, Online Tests, Previous Year
|
1365 videos|1312 docs|1010 tests
|
FAQs on Constraints and Database Schemas Video Lecture - SSC CGL Tier 2 - Study Material, Online Tests, Previous Year
| 1. What are constraints in a database schema? |  |
Ans. Constraints in a database schema are rules or conditions that are imposed on the data stored in a database. They ensure that the data follows certain criteria or relationships, maintaining the integrity and consistency of the database. Constraints can include rules such as unique values, primary key constraints, foreign key constraints, and check constraints.
| 2. How do constraints help in maintaining data integrity? | |
Ans. Constraints play a crucial role in maintaining data integrity in a database. They enforce rules and conditions on the data, preventing it from being inserted, updated, or deleted in a way that violates the defined criteria. Constraints such as unique constraints ensure that each value in a column is unique, while foreign key constraints maintain referential integrity by enforcing relationships between tables.
| 3. What is the difference between primary key and foreign key constraints? | |
Ans. A primary key constraint is used to uniquely identify each record in a table. It ensures that the values in the specified column(s) are unique and cannot be null. On the other hand, a foreign key constraint establishes a relationship between two tables. It enforces referential integrity by ensuring that the values in a column of one table match the values in another table's primary key column.
| 4. How do check constraints work in a database schema? | |
Ans. Check constraints allow the definition of conditions that the data must meet before being inserted or updated in a table. These conditions can be based on logical expressions, comparisons, or patterns. Check constraints are used to restrict the values that can be stored in a column, ensuring that they meet specific criteria.
| 5. Can constraints be modified or dropped after they are created? | |
Ans. Yes, constraints can be modified or dropped after they are created. In most database management systems, there are commands or statements available to alter or drop constraints. However, it is important to consider the impact of modifying or dropping constraints on the data integrity and consistency of the database. It is recommended to carefully evaluate and plan any changes to constraints before implementing them.
Text Transcript from Video
hello friends welcome back in this
tutorial we will study about constraints
on databases there are many restrictions
or constraints on the actual values in a
database state constraints on databases
can be divided into three categories
first is inherent model based
constraints or implicit constraints
these are the constraints that are
inherent in the data model for example
the constraint that a relation cannot
have duplicate tuples is an inherent
constraint of the relational model
second is a schema based constraints or
explicit constraints a schema based
constraints are explicit constraints are
constraints that can be directly
expressed in the schema of the data
model by specifying them in the DDL for
example key constraints domain
constraints and entity integrity
constraints are constraints that can be
expressed in a schema of the relational
model domain constraints are schema
based constraints of the relational
model domain constraints specify that
within each tuple the value of each
attribute a must be an atomic value from
the domain of attribute P
third is application-based
our semantic constraints these are the
constraints that cannot be directly
expressed in the schema of the data
model so they must be expressed and
enforced by the application programs
thank you very much
tutorial we will study about constraints
on databases there are many restrictions
or constraints on the actual values in a
database state constraints on databases
can be divided into three categories
first is inherent model based
constraints or implicit constraints
these are the constraints that are
inherent in the data model for example
the constraint that a relation cannot
have duplicate tuples is an inherent
constraint of the relational model
second is a schema based constraints or
explicit constraints a schema based
constraints are explicit constraints are
constraints that can be directly
expressed in the schema of the data
model by specifying them in the DDL for
example key constraints domain
constraints and entity integrity
constraints are constraints that can be
expressed in a schema of the relational
model domain constraints are schema
based constraints of the relational
model domain constraints specify that
within each tuple the value of each
attribute a must be an atomic value from
the domain of attribute P
third is application-based
our semantic constraints these are the
constraints that cannot be directly
expressed in the schema of the data
model so they must be expressed and
enforced by the application programs
thank you very much
About this Video
|
4.69/5 Rating |
|
Nov 15, 2024 Last updated |
Video Description: Constraints and Database Schemas for SSC CGL 2024 is part of SSC CGL Tier 2 - Study Material, Online Tests, Previous Year preparation.
The notes and questions for Constraints and Database Schemas have been prepared according to the SSC CGL exam syllabus.
Information about Constraints and Database Schemas covers all important topics for SSC CGL 2024 Exam.
Find important definitions, questions, notes, meanings, examples, exercises and tests below for Constraints and Database Schemas.
Introduction of Constraints and Database Schemas in English is available as part of our SSC CGL Tier 2 - Study Material, Online Tests, Previous Year for SSC CGL & Constraints and Database Schemas in
Hindi for SSC CGL Tier 2 - Study Material, Online Tests, Previous Year course. Download more important topics related with notes, lectures and mock test series for
SSC CGL Exam by signing up for free.
Description
Video Lecture & Questions for Constraints and Database Schemas Video Lecture | SSC CGL Tier 2 - Study Material, Online Tests, Previous Year - SSC CGL full syllabus preparation | Free video for SSC CGL exam to prepare for SSC CGL Tier 2 - Study Material, Online Tests, Previous Year.
Information about Constraints and Database Schemas
Here you can find the meaning of Constraints and Database Schemas defined & explained in the simplest way possible.
Besides explaining types of Constraints and Database Schemas theory, EduRev gives you an ample number of questions to practice Constraints and Database Schemas tests,
examples and also practice SSC CGL tests.
|
1365 videos|1312 docs|1010 tests
|
|
Explore Courses for SSC CGL exam
|
|
Signup for Free!
Signup to see your scores go up within 7 days! Learn & Practice with 1000+ FREE Notes, Videos & Tests.
Related Searches
Viva Questions
,Previous Year
,Constraints and Database Schemas Video Lecture | SSC CGL Tier 2 - Study Material
,Previous Year Questions with Solutions
,shortcuts and tricks
,video lectures
,practice quizzes
,Exam
,Summary
,Semester Notes
,Sample Paper
,Constraints and Database Schemas Video Lecture | SSC CGL Tier 2 - Study Material
,Online Tests
,past year papers
,Objective type Questions
,Constraints and Database Schemas Video Lecture | SSC CGL Tier 2 - Study Material
,Extra Questions
,Free
,Previous Year
,study material
,mock tests for examination
,ppt
,Online Tests
,Previous Year
,MCQs
,Important questions
,Online Tests
;
Study Constraints and Database Schemas on the App
Students of SSC CGL can study Constraints and Database Schemas alongwith tests & analysis from the EduRev app,
which will help them while preparing for their exam. Apart from the Constraints and Database Schemas,
students can also utilize the EduRev App for other study materials such as previous year question papers, syllabus, important questions, etc.
The EduRev App will make your learning easier as you can access it from anywhere you want.
The content of Constraints and Database Schemas is prepared as per the latest SSC CGL syllabus.
|
© EduRev
|
Education Revolution
|
Follow Us
|
Signup to see your scores
go up within 7 days!
Access 1000+ FREE Docs, Videos and Tests
Takes less than 10 seconds to signup