Sql rewrite layer detection for differential privacy

One or more computer-readable storage medium storing one or more instructions that, when executable by one or more computers, cause the one or more computers to perform operations comprising:

• identifying a SQL query;
• identifying one or more source tables against which the SQL query will be processed and a classification of each source table;
• generating a parse tree based on the SQL query, the parse tree comprising the one or more source tables, an output table, and at least one operation;
• searching the parse tree for operations to re-write by:
• selecting a current branch to search;
• performing, as an analyzed operation, an analysis of each operation in the current branch starting at the output table and for each operation:
• determining whether the analyzed operation is an aggregation process that transforms a user-level detailed table (ULDT) into an aggregate table;
• in response to the operation being an aggregation process that transforms a user-level detailed table (ULDT) into an aggregate table:
• re-writing the operation with a differential privacy (DP) operation;
• in response to the operation not being an aggregation process that transforms a ULDT into an aggregate table:
• proceeding to the next operation in the current branch;
• selecting a next branch as the current branch;
• and
• repeating the analysis until each branch of the parse tree has been searched.

A computer-implemented system, comprising:

• one or more computers;
• and
• one or more computer memory devices interoperably coupled with the one or more computers and having computer-readable storage media storing one or more instructions that, when executed by the one or more computers, perform one or more operations comprising:
• identifying a SQL query;
• identifying one or more source tables against which the SQL query will be processed and a classification of each source table;
• generating a parse tree based on the SQL query, the parse tree comprising the one or more source tables, an output table, and at least one operation;
• searching the parse tree for operations to re-write by:
• selecting a current branch to search;
• performing, as an analyzed operation, an analysis of each operation in the current branch starting at the output table and for each operation:
• determining whether the analyzed operation is an aggregation process that transforms a user-level detailed table (ULDT) into an aggregate table;
• in response to the operation being an aggregation process that transforms a user-level detailed table (ULDT) into an aggregate table:
• re-writing the operation with a differential privacy (DP) operation;
• in response to the operation not being an aggregation process that transforms a ULDT into an aggregate table:
• proceeding to the next operation in the current branch;
• selecting a next branch as the current branch;
• and
• repeating the analysis until each branch of the parse tree has been searched.