SQL

Databases speak a language: SQL

Databases speak SQL To execute CRUD commands, most databases support the language SQL (structured query language). SQL is a relatively easy-to-learn language that allows you to perform CRUD transactions as a human being, as well as in an automated fashion via program artefacts.

If we were to filter the data from our address list by street, in SQL this might sound like

SELECT * FROM tblClients WHERE IDstreet=1 
DELETE * FROM tblStreets WHERE IDcity=2

Try and learn SQL on  https://www.w3schools.com/sql/trysql.asp?filename=trysql_asc

Learn SQL:  https://www.w3schools.com/sql/sql_select.asp