primary key , foreign key , constraints , sql documentation added

[dinesh-2047]

Description

I have added sql documentation (primary key , foreign key , constraints ).

Fixes #357

Type of Change

• New feature (e.g., new page, component, or functionality)
• Bug fix (non-breaking change that fixes an issue)
• UI/UX improvement (design, layout, or styling updates)
• Performance optimization (e.g., code splitting, caching)
• Documentation update (README, contribution guidelines, etc.)
• Other (please specify):

Changes Made

-created primary-key-foreign-key.md file and constraints.md file

Checklist

• My code follows the style guidelines of this project.
• I have tested my changes across major browsers/devices
• My changes do not generate new console warnings or errors , I ran npm run build and attached scrrenshot in this PR.
• This is already assigned Issue to me, not an unassigned issue.

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Project	Deployment	Preview	Comments	Updated (UTC)
recode-website	Ready	Preview	Comment	Aug 16, 2025 11:00pm