Normally refers to a variable length string data type.

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15
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1answer
21k views

Varchar(Max) field cutting off data after 8000 characters SQL Server 2008

I have a field to store some data, the field is declared as varchar(Max). To my understanding this should be storing 2^31 - 1 characters but when I enter some content over 8000 chars it cuts the rest ...
5
votes
2answers
780 views

varchar performance impact

This question has been asked before ( speed impact of using varchar in MSSQL 2008 ), but the answers are not detailed enough to my satisfaction. Admitedly this is not a current issue and mainly for ...
2
votes
2answers
116 views

Storing NULL Values in large VARCHAR fields

I have a table that represents a "note". This note has things like a title and various other meta data. However, I'm trying to figure out the best practice for storing the contents of the note. ...
2
votes
1answer
2k views

Oracle SQL count occurances of character in VARCHAR

Is is possible to count the number of occurrences of a character in a VARCHAR in oracle? Something that would allow me to determine '11001110' has 5 ones?
3
votes
1answer
415 views

MySQL text field without quote

I've just run into something strange. The base_id is a varchar(255). When I do a SELECT without quote, it scans the whole table: mysql> EXPLAIN SELECT sid FROM rf_fo.scald_atoms WHERE base_id = ...
11
votes
2answers
3k views

SQL Server VARCHAR Column Width

Searching around the web, I have found conflicting advice on whether there is a performance impact when specifying overly-wide VARCHAR columns, e.g. VARCHAR(255) when VARCHAR(30) will probably do. I ...
4
votes
1answer
4k views

Rows with a variable number of columns?

I'm trying to design a database for a program that is storing and manipulating tweets off of Twitter. I'm using code to fragment a tweet into words, usernames, and hashtags, so I'm meeting ...
1
vote
1answer
144 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
6k 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
752 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 ...
25
votes
3answers
27k 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 ...
5
votes
4answers
521 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. ...
21
votes
5answers
13k 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 ...