Mid From PDF SQL SQL & Databases

What are database constraints?

Q: What are database constraints?

Short answer: Can you give examples? Database Constraints are rules applied to ensure the integrity and accuracy of the data within a database. Examples include: NOT NULL: Ensures that a column cannot have a NULL value. UNIQUE: Ensures all values in a column are unique. CHECK: Ensures that all values in a column satisfy a specific condition. DEFAULT: Sets a default value for a column if no value is specified. FOREIGN KEY: Ensures… Explain a bit more the value in one table corresponds to a valid value in another table. Real-world example (ShopNest) ShopNest’s SQL Server database stores customers, products, and orders. Good indexes and clear foreign keys keep checkout queries fast and safe. Say this in the interview Define — one clear sentence (the short answer above). Example — relate it to a project like ShopNest or your real work. Trade-off — when you would not use it.

Short answer: Can you give examples? Database Constraints are rules applied to ensure the integrity and accuracy of the data within a database. Examples include: NOT NULL: Ensures that a column cannot have a NULL value. UNIQUE: Ensures all values in a column are unique. CHECK: Ensures that all values in a column satisfy a specific condition. DEFAULT: Sets a default value for a column if no value is specified. FOREIGN KEY: Ensures…

Explain a bit more

the value in one table corresponds to a valid value in another table.

Real-world example (ShopNest)

ShopNest’s SQL Server database stores customers, products, and orders. Good indexes and clear foreign keys keep checkout queries fast and safe.

Say this in the interview

Define — one clear sentence (the short answer above).
Example — relate it to a project like ShopNest or your real work.
Trade-off — when you would not use it.

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