Normally refers to a variable length string data type.

learn more… | top users | synonyms

1
vote
1answer
140 views

String Pooling for MySQL

So I'm having this table that logs all errors happened in our production code. It looks like this: id | date | type | message | file | line ...
4
votes
3answers
5k views

Does an Oracle nvarchar2 take twice as much space as varchar2?

Regarding point 4 of this question (which is in reference to MS SQL Server): VARCHAR does not store Unicode characters. NVARCHAR does store Unicode characters. Today's applications should ...
5
votes
3answers
708 views

Why is Row Overflow not working on SQL Server 2005

I have a SQL Server 2005 database with a table that has around 860 columns. Aside from the ID column all other columns are varchar(N) where N is either 100 or 500. Upon inserting a new row (via an ...
13
votes
3answers
2k views

Is there any point in undersizing VARCHAR columns?

Googling around there seems to be mixed reports whether the size of a VARCHAR2 column in Oracle impacts performance or not. I would like to give the question of VARCHAR size a little twist and hope ...
18
votes
4answers
2k views

What are the consequences of setting varchar(8000)?

Since varchar takes disk space proportional to the size of the field, is there any reason why we shouldn't always define varchar as the maximum, e.g. varchar(8000) on SQL Server? On create table, if ...
19
votes
3answers
24k views

What is the performance impact of using CHAR vs VARCHAR on a fixed-size field?

I have an indexed column that stores an MD5 hash. Thus, the column will always store a 32-character value. For whatever reason, this was created as a varchar rather than a char. Is it worth the ...
4
votes
4answers
482 views

How much will using a varchar(15) PK affect my tables performance?

I am parsing log file lines from a legacy, proprietary application into a nice easy to query DB. The log lines have no unique integer ID. They do have a UNIX timestamp as an 8 character hex string. ...
5
votes
3answers
2k views

Which problems arise, declaring the size of all varchar parameters as max in stored proc?

Looking at this question, it seems, that other sites too have the problem of increasing column sizes in the process of time. Increasing just the size of a column in a table is a rather simple task. ...
20
votes
5answers
10k views

Performance implications of MySQL VARCHAR sizes

Is there a performance difference in MySQL between varchar sizes? For example, varchar(25) and varchar(64000). If not, is there a reason not to declare all varchars with the max size just to ensure ...