CHAR vs VARCHAR - no real difference size on disk 1

[AlastairP]

Good morning all

I am looking for ways to optimize a database.
I have used CHAR field types for the database.
I took a look at the VARCHAR field type.
According to the documentation, VARCHAR only uses the size that it needs unlike CHAR that pads the field to the full width.
Therefore you would expect a table with a VARCHAR field to have less size on disk for a comparative example.

I created 2 tables with 2 fields each - autoinc ID field and character field width 100
One of the tables the character field is VARCHAR the other CHAR
I added 10k records to each with just one character in the text field.
Other than a minor difference of size, the size on disk was the same, about 10mb.

So what good is a varchar field if it does not save size on disk, is there something I am missing?
Other than the text from varchar fields not requiring TRIM() etc?

 

[TamarGranor]

Varchar exists mostly to make it easier to move data in and out of remote tables. In VFP, all fields stored in a DBF are fixed-length. Period.

Tamar

 

[AlastairP]

Ok Thanks Tamar

 

[Mike Lewis]

For more information on this subject, glance at my article: Solving the "padded varchar" problem.

Mike

__________________________________
Mike Lewis (Edinburgh, Scotland)

Visual FoxPro articles, tips and downloads

 

[AlastairP]

Thanks Mike,
I won't be using remote views in this case, but very interesting to know, thankyou.


Alastair