The SQL Language Presented by Reggie James, Isel Liunoras, and Chris Rollins

Table of Contents  What is SQL?  History  Timeline  Features  Advantages/Disadvantages  Programming Examples  Conclusion

What Is SQL?  SQL stands for Structured Query Language  SQL is a declarative language  Results in one statement of the desired result (i.e. ML and Haskell)  Unlike procedural languages (many lines of code)  Used for RDBMS (Relational Database Management System)

History of SQL

 In 1970, Dr. E “Ted” Codd introduced the relational model for databases  In 1974, IBM started to develop System/R (predecessor to SQL)  In 1978, System/R released by IBM  In 1982, IBM released SQL/DS and DB25  The versions used today are SQL 89, SQL 92 and SQL 99. Most businesses are still using SQL 92

Dr. E.F. “Ted” Codd

Relational Data Model  Data model used for business data management  In this model, data are organized into tables  The set of names of the columns is called the schema of the table

Timeline of SQL

Features of SQL

 Runs queries of databases  Exists on Windows and UNIX platforms  There are different versions of SQL that are still existing  Backwards compatible

Disadvantages and Advantages

Disadvantages  Code cannot be reused  Can’t link databases graphically

Advantages to SQL  User can customize query with unlimited parameters  Takes up less space than the GUI interfaces such as: Access and Paradox  Easy to learn  High Productivity  Integration with Oracle and Microsoft

Programming Examples

Programming Example LOOP over each student record IF this record has major = ‘Nutrition’ THEN DELETE this record; END IF; END LOOP;

Another Programming Example DECLARE V_NewMajor VARCHAR2(10) := ‘History’; V_FirstName VARCHAR2(10) := ‘Scott’; v_LastName VARCHAR2(10) := ‘Urman’; BEGIN UPDATE students SET major = v_NewMajor WHERE first_name = v_LastName; IF SQL%NOTFOUND THEN INSERT INTO students (ID, first_name, last_name, major) VALUES (student_sequence.NEXTVAL,v_FirstName,v_LastName, v_NewMajor); END IF; END;

Conclusion  SQL is a very powerful query language provided that the user is familiar  SQL is relatively easy to learn  Upcoming product releases will change the relative strengths of the database management systems  Making it more powerful  Making it more efficient