Databases

📌 Planned placeholder page: this page is reserved for "MySQL, PostgreSQL, MongoDB", and the content will be filled in progressively along with learning.

Planned Content

• [ ] Index internals (B+ tree) and execution plans
• [ ] Transactions, isolation levels and MVCC
• [ ] SQL optimization real-world cases
• [ ] Sharding and data migration strategies

Next Steps

• [ ] Complete this page item by item against the planning checklist in the Domain Overview
• [ ] Add runnable examples and pitfall records for each entry
• [ ] Change the status from "Planned" to "Collected" when done

For writing guidelines, please refer to the Domain Overview.