如何更新特定行的aws redshift

Question

I'm using lambda function to handle update of redshift table row using boto3. Scenario is frontend will send data via api gateway that includes primary key and complete row that needs to updated in redshift, api gateway initiate lambda for update. Issue is I'm not able to find a solution using which I can update complete row of matching primary key. as per AWS doc. Update command can be used but in Set column I have to pass each attribute and it's value like:

eg:

Update test_table
Set col1 = "test1", col2 = "test3" ....

as frontend use lots of table I'll not be able to do this way.

api gateway sample response for lambda:

'attribute':['col1', 'col2', 'col3', 'col4', ....], 'value':['test1', 'test2', 'test3', 'test4', ....]

Any solution how to do it will be great help.

Answer 1

Redshift, internally, doesn't update data - it deletes and replaces the row(s). I'd recommend that you just follow this pattern and delete the row based on the PK and then insert the replacement row. You will need to do this within a transaction block so no 3rd party can see the row "missing", only old value or new value.

Your delete code pattern is consistent as is you insert pattern. This should make coding this up in the lambda much simpler.

Also, please remember that Redshift doesn't ensure uniqueness of PKs and that ensuring the PK are unique is up to the user (you or your ETL processes). This has nothing to do with implementing the above solution, it is just a common mistake when using Redshift with PKs.