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  3. Introduction to Databases in Python

Exercise

Deleting specific records

By using a where() clause, you can target the delete statement to remove only certain records. For example, Jason deleted all rows from the employees table that had id 3 with the following delete statement:

delete(employees).where(employees.columns.id == 3)

Here you'll delete ALL rows which have 'M' in the sex column and 36 in the age column. We have included code at the start which computes the total number of these rows. It is important to make sure that this is the number of rows that you actually delete.

Instructions

100 XP
  • Build a delete statement to remove data from the census table. Save it as delete_stmt.
  • Append a where clause to delete_stmt that contains an and_ to filter for rows which have 'M' in the sex column AND 36 in the age column.
  • Execute the delete statement.
  • Hit 'Submit Answer' to print the rowcount of the results, as well as to_delete, which returns the number of rows that should be deleted. These should match and this is an important sanity check!