Projection constraints in a query processing system

A system comprising:

• one or more hardware processors of a machine;
• and
• at least one memory storing instructions that, when executed by the one or more hardware processors, cause the system to perform operations comprising:
• receiving, by at least one hardware processor, a first query directed towards a shared dataset, the first query identifying a first operation and including available values specifying data that is accessible by query requests;
• accessing a first set of data from the shared dataset to perform the first operation, the first set of data including data accessed from a first column of the shared dataset;
• determining that a projection constraint policy is attached to the first column, the projection constraint policy restricting output of data values stored in the first column;
• determining, based on a context of the first query, that the projection constraint policy should be enforced in relation to the first query;
• and
• generating an output to the first query based on the first set of data and the first operation, the output to the first query not including data values stored in the first column based on determining that the projection constraint policy should be enforced in relation to the first query.

A non-transitory computer-readable medium storing instructions that, when executed by one or more computer processors of one or more computing devices, cause the one or more computing devices to perform operations comprising:

• receiving, by at least one hardware processor, a first query directed towards a shared dataset, the first query identifying a first operation and including available values specifying data that is accessible by query requests;
• accessing a first set of data from the shared dataset to perform the first operation, the first set of data including data accessed from a first column of the shared dataset;
• determining that a projection constraint policy is attached to the first column, the projection constraint policy restricting output of data values stored in the first column;
• determining, based on a context of the first query, that the projection constraint policy should be enforced in relation to the first query;
• and
• generating an output to the first query based on the first set of data and the first operation, the output to the first query not including data values stored in the first column based on determining that the projection constraint policy should be enforced in relation to the first query.