[igCS] Database Query

Learn about what is database query and why we need it

Types of querying method

Filtering results from data in the Db with the given criteria

(imagine it as a question to ask the computer about data)

All students that wear glasses

All students from F4B

All students where they are NOT from F4B

All students who's glasses=Yes AND from F4B

All students where class=F4B AND class=F4C

One most common language for database is called SQL (Structural Query Language)

SQL is supported by most major database system

MS Access also supports using GUI in query building, we call it QBE (Query By Example)

SELECT * FROM Students WHERE class="F4B"

translates to: Select all students which class is F4B

We will create in Access...

All students who's glasses=Yes AND from F4B

All students who's LastName starts with 'C'

All students who is wearing glasses OR who is from F4A

All students, who's class is F4A, order by their LastName, displays ONLY their firstName and glasses

All students, who's NOT wearing glasses, order by their LastName, displays ONLY their firstName and class