Database Structures
R.D.M.S. = Relational Database Management Systems
(can access relational info from various tables)
D.B.2 = Big, expensive
ORACLE = Big, expensive
SQllite = free
mySQL = free = what we’re using
SQL = Structrured Query Language
SQL = Language used to ask questions
ORACLE/mySQL etc. translates info slightly different.
SQL Command to create database is
Create Database (andrea_database )
Column = Field
Row = Record
Field names cannot have spaces.
Every Record in a Db has to be completely unique.
Must have a mechanism to make sure Db records are unique.
(accession number)
Most common DATA TYPES:
PRIMARY KEY: generates unique # for records.
End of primary key # should always be ID therefore you always know what the primary key # is.
Primary Key type is almost always INT (integer/whole number).
VARCHAR = Variable Character Length = allows you to keep the size of memory set aside to a minimum.
ex. VARCHAR 30 (store characters up to the # 30) Maximum VARCHAR for mySQL is 255.
If you need more characters than 255, use TEXT or BLOB. BLOB is for more text/info.
Salary = FLOAT = Floating point #; #’s with a decimal.
DATE =
NAMING CONVENTIONS:
Name of Database/ Field/ Table
Rule #1: Make the name as descriptive as possible: explicitly state what they contain.
Rule #2: For 2 word field: lowerCase firstWord, upperCase secondWord firstNameHere
