SQL is the language used to communicate to relational database management systems (RDBMS). E.F. Codd wrote a paper in 1970 describing a completely different way of structuring data. Up till then, data was generally organized in a hierarchical structure of some kind and a lot of code was needed to work with the stored data. Codd’s paper described a structure of storing data as relationships to reality as objects that have ties to other objects in the data structure.