topic Re: How can I check that column on a delta table has a "NOT NULL" constraint or not? in Data Engineering

How can I check that column on a delta table has a "NOT NULL" constraint or not?

Lon_Fortes — Wed, 18 Aug 2021 15:30:42 GMT

Title pretty much says it all -

I'm trying to determine whether or not a column on my existing delta table was defined as NOT NULL or not. It does not show up in any of the metadata (describe detail, describe history, show tblproperties).

Thanks in advance

Re: How can I check that column on a delta table has a "NOT NULL" constraint or not?

Lon_Fortes — Wed, 18 Aug 2021 16:38:20 GMT

I've found a solution, the following scala serves my needs:

val table = spark.table("<database>.<tablename>")

val schema = table.printSchema

Re: How can I check that column on a delta table has a "NOT NULL" constraint or not?

Matthew8 — Thu, 19 Aug 2021 07:19:10 GMT

walgreenslistens Wrote:

A UNIQUE constraint defines a set of columns that uniquely identify rows in a table only if all the key values are not NULL. If one or more key parts are NULL, duplicate keys are allowed.

Re: How can I check that column on a delta table has a "NOT NULL" constraint or not?

muki — Wed, 07 Jan 2026 22:42:09 GMT

if using python, we can use

display(spark.catalog.listColumns('<catalog>.<schema>.<table>'))

Re: How can I check that column on a delta table has a "NOT NULL" constraint or not?

iyashk-DB — Thu, 08 Jan 2026 08:11:43 GMT

@muki , you can run
SHOW CREATE TABLE <catalog>.<schema>.<table>

and in that also you can also see the constraints applied.