CSE 278 Lecture Notes - Lecture 12: Shema Yisrael, Tuple, Data Definition Language
17 Oct 2018
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Insert into movies values ( in heat of night", 1068, 121, drama"), Can add or drop attributes once we have a table for that purpose using alter table with. Assuming the moviestar table has been created. Tuple inserted at later time may not provide all the values of all attributes in schema. When attribute is not yet determined, it becomes null, *, unless default value is defined. Create table beer { name varchar(20), manf varchar(30) More flexible, as it"s the only way to specify a key involving more than one attribute, which is often case. Both can be used to specify key, tho there is subtle difference. If attribute is declared as primary key, then the attribute and the tuple in the table must have a value. If an attribute is declared as unique, it can be null. The most popular language for relational databases is sql (structured query language)
