IMCA - Introduction to RDBMS

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List DCL and TCL commands.

DCL – Data Control Language

These commands are used to manage user permissions and access in the database.

**GRANT** | Gives users access privileges to database objects (like tables, views, etc.)
**REVOKE** | Removes previously granted privileges
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Explain check constraint with example

A CHECK constraint is used in SQL to limit the values that can be inserted or updated in a column of a table. It ensures that all values in a column satisfy a specific condition.

If the condition evaluates to TRUE , the value is accepted. If it's FALSE or UNKNOWN ,
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List characteristics of SQL.

1. **Used to Work with Tables**
SQL helps you create, manage, and get data from tables in a database.

2. **Easy to Learn and Use**
It uses simple English-like commands like `SELECT`, `INSERT`, `UPDATE`, `DELETE`.
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Define Candidate Key and Unique Key

A Candidate Key is a column or a combination of columns in a table that can uniquely identify each row in that table. It must contain unique values and cannot contain nulls. There can be more than one candidate key in a table, but only one of them becomes the Primary Key .

A Unique
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What is Data Model ?

A Data Model in RDBMS is a way to describe how data is organized, stored, and related in a database. It defines the structure of tables, the relationships between them, and the rules that ensure data is stored accurately and consistently.

In simple terms, it's shows
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What is weak entity ?

A weak entity in a relational database is an entity that cannot be uniquely identified by its own attributes alone.

It relies on a relationship with another entity, known as the strong entity , to establish its identity.

This means a weak entity
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