? One-to-One Relation
An entity may be related to zero or one entity
in another entity set.

? Like Chairman – Department Relation

Entity ? Relationship model is a Database design tool for creating a diagram.
( ?entity? means record, object )


? Binary Relationship Set
? Ternary Relationship Set


There are kinds of attributes. Some of them is like that:


? Single valued attribute: at most one value
?Multi-valued attribute: 0 or more similar values. We don?t put them to the E-R diagram, but we can…

Basic terms which we will use in this lecture:
schema = structure
instance = data
data dictionary (containing name of the tables)


SQL is a
-data management language:
insert a record, update a record, delete a record
-query language: select
…

Hey, i decided to share my database notes with you.


Not all of them, but just the important parts.


I hope they are gonna be useful for you:)


Hope to start it immediately, by!