CSDN
Latest recorded position: #25 on Oct 9, 2026, 8:01 PM CST.
Across 1 retained daily record, the best recorded rank was #25. From the first retained rank (#25) to the last (#25), this listing held the same rank.
MySQL Table Constraints Explained: From Null Attributes to Foreign Keys
MySQL 表的约束详解：从空属性到外键
ThreadEast first recorded "MySQL Table Constraints Explained: From Null Attributes to Foreign Keys" on Oct 9, 2026, 8:01 PM CST. It has been observed on CSDN, with less than one hour between the first and latest recorded appearances.
What the trend data tells us
The English title describes the topic of the source listing. Its appearance in a ranking measures attention within that platform; the ranking alone does not explain the cause of a spike or verify the underlying claim.
This stable URL remains available after a topic leaves a live ranking. Observation span is elapsed time between sightings, not continuous time on a chart. Platforms use different ranking and heat systems; their metrics are not added together.
Original evidence
Source listings
CS
CSDN
Chinese source / Guest articles; some require sign-in
#25Source metric: 2362
Original source Daily ranking timeline
Up to 180 recent daily records from retained observations and preserved archives. The best rank and last rank can differ within a day. Times use China Standard Time (UTC+8).
| Day | Platform | Best rank | Last rank | Observations |
|---|---|---|---|---|
| 2026-10-09 | CSDN | #25 | #25 | 1 |