What is a "modern" programming language?

I am creating a DBMS Language. What are "kernel," "schema," and "data validation" in programming languages?

• For a class project, I am trying to create my own programming language.. I came up with an idea of a NOSQL database management resembling syntax of MongoDB. For example, in my programming language, we can represent each table row in following way: object = {         name: "John",         sex: Male,         age: 19     } Well, I wrote a brief project proposal of this idea, and showed it to my professor. These are two feedbacks I got from him, and I'm not sure exactly what these mean.. "1. Since you have no enforced schemas, what forms of data validation are you offering, if any?"         "2. I suggest you create a small kernel of your language and implement a translator for this kernel.     Write a small MY_LANGUAGE_NAME program and run them through your translator." For 1, What does "enforced schema" mean, and what are examples of "data validation"...? For 2, I looked up "kernel program" on Wikipedia, but I don't understand the idea of it..... Also he told us to write a MY_LANGUAGE_NAME program (which is a database management sql language). There is no such thing as MySQL "Program" or Postgresql "program",, so I don't know what he means by this.. Since my professor is usually outside school and there is no way to contact him,, Can someone help me what the feedback means?

• Answer:

  A schema is a specification of the structure of a database (table names, fields, relationships, etc...). Enforced schemas would be the particular schemas your programming language permits for databases built using it. Data validation is just what it says: verifying that the provided data accords to predetermined rules. Your professor is saying that, given you are not restricting the databases to specified schemas, how will your language verify that the data submitted accords to your structure? (correct data types, etc...)