SQL Server DDL vs DML

For the longest time I’ve had a hard time remembering the difference between SQL Server DDL vs DML statements. I had a hard time remembering what statement fell under what category. Was INSERT, UPDATE, DELETE a DML command or DDL? What about CREATE / ALTER?  It was all confusing to me.

I finally figured out a way to remember the difference. Before I tell you my “secret”, here’s a quick explanation of each.

DDL

DDL, or Data Definition Language, consists of the following commands:

CREATE, ALTER and DROP

Below is an image taken straight from MSDN that includes all the DDL statements.

DDL vs DML SQL Server DDL

DML

DML, or Data Manipulation Language, consists of the following commands:

INSERT, UPDATE, DELETE, SELECT…

Below is an image taken straight from MSDN.

DDL vs DML SQL Server

How did I memorize the difference? Well, for DML the ‘M’ is for ‘manipulation’, so I automatically associate “INSERTING” or “UPDATING” data as “manipulating” data. Once I understood that, DDL became easy to remember and associated it with CREATE, ALTER, DROP. By memorizing one of them you automatically know the second. :)

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