There was one machine coding round.
The question was:
The objective is to design and implement an in-memory SQL-like database, which should support the following set of operations / functionality:

It should be possible to create or delete tables in a database.
A table definition comprises columns which have types. They can also have constraints
The supported column types are string and int.
The string type can have a maximum length of 20 characters.
The int type can have a minimum value of -1024 and a maximum value of 1024.
Support for mandatory fields (tagging a column as required)
It should be possible to insert records in a table.
It should be possible to print all records in a table.
It should be possible to filter and display records whose column values match a given value.

I was able to achieve some level of functionality. But was rightfully rejected.

Any insights on how to approach this would be great.