setrfest.blogg.se - Mysql timetag field autopopulate

Mysql timetag field autopopulate update#
Mysql timetag field autopopulate manual#
Mysql timetag field autopopulate code#
Mysql timetag field autopopulate series#

# ⓘ global attributesAny attributes permitted globally.

How do you input date and time in HTML?.

Additional constraints and admonitions #.

Mysql timetag field autopopulate update#

I like your UPDATE and SET using DEFAULT. Helpful to tie-together what changed (and coupled with a TRIGGER, which inserts DELETED values into a Audit Table, there is then lots of scope for investigating historical changes. That is useful because all table updates, within a single batch, get the same Transaction No. That is smallint (its only a tie break number) and Trigger resets it to 1 if it approaches 32KĪ 3rd party APP that we use also has a Transaction No. On a web form I include that as a HIDDEN form field, and when submitted by the user if it is different to the value in DB then someone else must have edited the record within that time. I have one additional System Column “EditNo” which is incremented (by trigger, if not done by user) to use for optimistic locking. For good measure I prefix the system column name with “z” so that anything that sorts the columns into Alpha order will list the System Columns last. I know the column order doesn’t matter, but it means that all System Columns are first / consistent and I find it annoying when more column definitions are added later and the “System” columns wind up in the middle.

My “System” columns are first in the table definition.

Mysql timetag field autopopulate code#

All triggers should be able to handle multi row operations!Īs with any time you add columns or database code, make sure that you test your application code carefully to make sure you haven’t introduced any bugs. This way my trigger will handle multi row updates as well as single row updates.

I’m joining the inserted system view to the original table using the primary key column(s).

This way the default values themselves are all in one place and if I need to change them they are. If you were wondering why I had defaults for the last update columns when the defaults are primarily for the inserts this is why.

I’m using the DEFAULT keyword in the update statement to refer back to the defaults for the column.

The IF UPDATE() statement lets me short circuit the trigger if someone is manually updating the last update columns.

This is an update only trigger because I’m only handling the last update columns.

Mysql timetag field autopopulate manual#

My particular use case is for application inserts/updates and I want to leave an option for manual changes without any extra work.

I could manage that with this trigger as well but I’m choosing not to. I should probably point out that defaults also don’t work if you specifically include the column in your command (i.e.

IF UPDATE(LastUpdateUser) AND UPDATE(LastUpdateDate) So, as much as I hate to do it we need a trigger. Now these defaults are only going to be useful for inserts and we want update information. You do want to pay somewhat careful attention to the data types you are using because, for example, the way I have it here adds an additional 116 bytes per row.

Mysql timetag field autopopulate series#

If you want to look at other options my friend Randolph West ( blog| twitter) has a fantastic series of posts on the date and time data types and functions. I talk about which user function does what here.įor the date columns I’m using the datetime data type, mostly because I’m lazy and this is kind of old code. However, depending on how your application connects to the database you may need to use something else. I typically use original_login() because it ignores impersonation. You might need more (or even less) or you could even use sysname. LastUpdateDate datetime CONSTRAINT df_LastUpdateDate DEFAULT getdate()įor the user columns I’m using a varchar(50) because that’s usually plenty. LastUpdateUser varchar(50) CONSTRAINT df_LastUpdateUser DEFAULT original_login(), Id INT NOT NULL IDENTITY(1,1) PRIMARY KEY,ĬreateUser varchar(50) CONSTRAINT df_CreateUser DEFAULT original_login(),ĬreateDate datetime CONSTRAINT df_CreateDate DEFAULT getdate(),