How should I best name my timestamp fields?

Question

When I am looking to create some timestamp fields (or other date/time style fields), what is the best way to name them? Should I just put record_timestamp?

Answer 1

You should describe the purpose of the column and not necessarily the data type. You can include date/time/timestamp in the name, but you should also include the meaning. For example

• CreationDate
• StartDate
• StatusTime
• Accessed
• Updated

Adding Date/Time/Timestamp and such at the end is particularly useful when the abscence of the addition would conflict with another column. For example, a table may need both a Status and a StatusTime.

Answer 2

How about xyz_at for a timestamp and xyz_on for a date field - eg start_at or start_on?

Normally I'd avoid including the data type in the field name - much better if you can infer what you need to know about the type from the name of any field (a field called description is unlikely to be an integer) - but being able to tell the difference between a timestamp and a date is often helpful.

Answer 3

I use:

• created_at
• updated_at

Answer 4

I found that using column names such as create_time, update_time and expire_time leads to better readability when it comes to method naming and specs (RSpec).

Answer 5

I looked at your profile and it says you work with SQL Server and in SQL Server TIMESTAMP data type has nothing to do with date or time and its used to kind of version stamping the rows. This is very useful in identifying which rows have been modified from a given point of time.

If you use TIMESTAMP then you don't have to specify a column name and SQL Server will create a column "TimeStamp" for you. But it is recommended to use "ROWVERSION" data type and in this case you have to specify the column name.

What's the best name for a column like this? It depends, and I would use something like VersionStamp, RV etc... What I consider important is NOT how you name it but are you using that consistently across the board.

HTH

Ref: http://msdn.microsoft.com/en-us/library/ms182776(v=sql.90).aspx

http://msdn.microsoft.com/en-us/library/ms182776.aspx

Answer 6

There is no exact right way to do it, only important thing is to be consistent across your code base and databases so developers are not confused.

Exact naming depends on the language conventions but I would choose one of the following below:

Python, Java, ORACLE/Postgresql
created_at, createdAt, CREATED_AT // Time when the record was created
updated_at, updatedAt, UPDATED_AT // Time when the record was last modified
started_at, startedAt, STARTED_AT // Some other record time
Or
create_time, createTime, CREATE_TIME
update_time, updateTime, UPDATE_TIME
start_time, startTime, START_TIME

Pretty much all fields are stored as timestamp, there will some fields required as date but usually they are more related to the business domain and could be named as per coming request

• birthday
• realase_date
• business_day

All timestamp fields to be stored in UTC.

Answer 7

I prefer using conventions that already exist.

Unix and programming languages have a widely accepted convention of mtime for Modification Time

For creation time,

• BSD and Windows use birthtime
• Windows also uses Creation Time
• xstat uses btime
• ext4 uses crtime
• JFS and btrfs use otime (don't ask, guessing "origination").

So for me, I pick mtime, and crtime for meta data.

For user supplied data, I go with what the field represents. If it's a birthday, I just say user_birthday.

As far as precision, for some it seems to hang them up on too much precision. You can store your birthdate as a timestamp (after all you were technically birthed at a time of day), but the SQL spec has casts from higher-precision to lower precision so if you're using a decent database this shouldn't be an issue. In your app itself, you can always truncate when needed. That is to say, I would never go birthday_date.

Answer 8

As suggest by @Evan Carroll, go with the existing standards unless you have strong reason to break the pattern.

If this is something new then you can follow any answer which best suits you.

I use *_on and *_by because it helps me to keep it consistent for when and who of the row:

- created_on & created_by
- updated_on & updated_by
- deleted_on & deleted_by -- soft delete
- approved_on & approved_by

Answer 9

In order to maintain consistency accross column names, I would suggest you to the following syntax:

dateCreated
dateUpdated
dateAccessed
dateStarted
date...

Answer 10

I prefer to use a prefix of DT for date stamps. For example: DTOpened, DTClosed, DTLastAccessed. This lets me list out all the DTxxxx for a quick reference of all date stamps in a given table.

Answer 11

I work for Texas Instruments, and on their systems they use xxxx_dttm

Answer 12

I would used a meaningful prefix and _TSMP as a suffix e.g. CREATION_TSMP or LAST_UPDATE_TSMP

Answer 13

For timestamps:

e.g. 2022-09-12T00:00:00Z

• updated_at
• created_at

It's concise and if used as a standard there's not confusion.

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For dates:

e.g. 2022-09-12

• updated_on
• created_on

The same comment from timestamps. It's concise and when used as a standard it's not confusing.

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For times without dates which is generally used for scheduling more than recording a time something occurred as that would be a timestamp:

e.g. 12:30:00

• send_time
• run_time

Since this is not used nearly as frequently in my experience as at and on using time is sufficient, plus it's short enough.

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There was a comment about _at being used for locations. While I can understand that I haven't worked at a business where locations of events was needed. For something like user's ip information we would just have something ip_country, ip_city, etc. For other types of locations we would use location_id. If you need locations and _at is confusing then by all means use a different standard.

I personally care more about consistency and having a standard than a particular standard, as long as there's backing for that standard and not something made up randomly.