180 likes | 201 Views
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
E N D
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)
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 History of SQL
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
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
Code cannot be reused Can’t link databases graphically Disadvantages
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 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