Question

I have a very simple textbox in a front end application (like php although the language doesn’t matter) and is inserting into the description column in a table in the Database defined below:

Table (ID[primary key], description[varchar(255)])

Although it will not happen often, at times there will be a need to insert more than 255 characters for one tuple. I could increase the length of the varchar but there are restrictions for the tuple size so to play it safe kept it at the recommended maximum 255.

The only way I could figure out how to do this would be to have 2 tables and split the text up into 255 character pieces. Tables defined as:

Table1 (ID[primary key]……….)

Table2 (ID, table1ID[foreign key to table 1] description[varchar(255)])

Is there a better way to achieve this?

Edit: Mysql version 5.5.11
Wasn’t aware there was a text data type. Probably new. Sounds like a type of application object but is it flexible enough to on average store 150 characters and 10% of the times store close to 5000 characters?

Answer 1

If using MySQL version 5.0.3 or later, you can just increase the size of your VARCHAR. According to the manual:

Values in VARCHAR columns are variable-length strings. The length can be specified as a value from 0 to 255 before MySQL 5.0.3, and 0 to 65,535 in 5.0.3 and later versions. The effective maximum length of a VARCHAR in MySQL 5.0.3 and later is subject to the maximum row size (65,535 bytes, which is shared among all columns) and the character set used. See Section E.7.4, “Table Column-Count and Row-Size Limits”.

To do this you would do:

ALTER TABLE tablename MODIFY description VARCHAR(...) [NOT] NULL;

Or you could use the TEXT type:

ALTER TABLE tablename MODIFY description TEXT [NOT] NULL;