![postgresql varchar postgresql varchar](https://cdn.educba.com/academy/wp-content/uploads/2020/07/PostgreSQL-log_statement-8.jpg)
With one minor exception, the only time I use char() is when I want the meta-data to say this MUST have have x-characters. text and varchar perform (almost) the same.
![postgresql varchar postgresql varchar](https://4.bp.blogspot.com/-3AlPlt04Y-Y/Wc4sRJSr5aI/AAAAAAAAD-U/2SQcvhIskcgEP8VR8AYFuQ4glAIYS3e7wCK4BGAYYCw/s1600/Untitled1.png)
I agree with everything said by a_horse_with_no_name, and I generally agree with Erwin's comment advice: Just use varchar (or text in Postgres) and forget that char exists. If the length of the char column is always used completely (so no padding occurs), then the above quote is wrong (at least for Postgres and Oracle)įrom my point of view, the char data type does not really have any real-word use. The above quote is only true if (and only if) the char column is defined too wide (i.e. So the only difference is the padding that is done for the char data type.Īlso keep in mind that there's often a very big difference between a CHAR and a VARCHAR when doing index comparisons If you declare both with the length of 10 characters and always store exactly 10 characters in them, then there is absolutely no difference whatsoever (this is true for Oracle and Postgres)
#Postgresql varchar plus#
So if you define a column as char(100) and one as varchar(100) but only store 10 characters in each, the char(100) column uses 100 characters for each value (the 10 characters you stored, plus 90 spaces), whereas the varchar column only stores 10 characters.Ĭomparing 100 character with 100 characters is going to be slower than comparing 10 characters with 10 characters - although I doubt you can actually measure this difference in a SQL query. However, there is one difference that can make a difference in performance: a char column is always padded to the defined length. There is no difference in speed when using those data types.
![postgresql varchar postgresql varchar](https://cache.yisu.com/upload/information/20201225/112/2205.jpg)
CHAR and VARCHAR are implemented exactly the same in Postgres (and Oracle).