DB File Structures
- Unordered Heap Files
- Clustered Heap Files
- Records and pages are grouped
- Sorted Files
- Pages and records are in sorted order
- Index Files
- B+ Trees, Linear Hashing, …
- May contain records or point to records in other files
Records
- Fixed Length Records (FLR)
- Variable Length Records (VLR)
- Slotted Page
- each page uses a page footer that maintains a slot directory tracking slot count, a free space pointer, and entries.
- The slot count tracks the total number of slots. This includes both filled and empty slots.
- The free space pointer points to the next free position within the page.
- Full when footer and records come together.
![image.png](https://img.ynchen.me/2023/02/b199ff4a25ab7b5f3183594684cc904e.webp)