The ease and ubiquity of SQL have even led the creators of many “ NoSQL ” or non-relational data stores, such as Hadoop, to adopt subsets of SQL or come up with their own SQL-like query languages.

SQLite will assume an explicitly named integer primary key is just an alias for the rowid if the type is spelled out as "INTEGER" rather than "INT." I can simply change my create table statement as ...

MySQL table primary keys and unique indexes prevent multiple rows with the same index from being added to the table. If you try to insert a duplicate row with a standard INSERT statement, you will ...