?pathtotake?
New member
http://databases.about.com/od/specificproducts/a/normalization.htm
From the above website it says:
for first NF
"Create separate tables for each group of related data and identify each row with a unique column or set of columns (the primary key). "
and for second NF it says:
"Remove subsets of data that apply to multiple rows of a table and place them in separate tables. "
What is the difference between those two statements?
The both create other tables yes. Thats all I understand.
I understand 1st NF.
When it says:
Remove subsets of data that apply to multiple rows of a table and place them in separate tables.
What are "subsets of data"?
what does it mean when it says "that apply to multiply rows"?
If you could use the simplest of vocabulary.
Thanks
I understand primary keys, foreign keys, and understand the problems that exist when there are duplicative data. I can normalize a database to a certain extent. I just can not grasp the differences between 1st, 2nd, and 3rd NF
And for 3rd NF it says:
"Remove columns that are not dependent upon the primary key. "
Dependant on the primary key?
How does that make sense?
From the above website it says:
for first NF
"Create separate tables for each group of related data and identify each row with a unique column or set of columns (the primary key). "
and for second NF it says:
"Remove subsets of data that apply to multiple rows of a table and place them in separate tables. "
What is the difference between those two statements?
The both create other tables yes. Thats all I understand.
I understand 1st NF.
When it says:
Remove subsets of data that apply to multiple rows of a table and place them in separate tables.
What are "subsets of data"?
what does it mean when it says "that apply to multiply rows"?
If you could use the simplest of vocabulary.
Thanks
I understand primary keys, foreign keys, and understand the problems that exist when there are duplicative data. I can normalize a database to a certain extent. I just can not grasp the differences between 1st, 2nd, and 3rd NF
And for 3rd NF it says:
"Remove columns that are not dependent upon the primary key. "
Dependant on the primary key?
How does that make sense?