Why should I use VARCHAR?
As the name suggests, varchar means character data that is varying. SQL varchar usually holds 1 byte per character and 2 more bytes for the length information. It is recommended to use varchar as the data type when columns have variable length and the actual data is way less than the given capacity.
Should I use text or VARCHAR Postgres?
Different from other database systems, in PostgreSQL, there is no performance difference among three character types. In most cases, you should use TEXT or VARCHAR . And you use the VARCHAR(n) when you want PostgreSQL to check for the length.
Is there any reason to use varchar over text?
The text column is a specialized version of BLOB and has restrictions on indexing. Just these two examples can be extrapolated to the other SQL RDBMS systems and should be reason enough to understand when to choose one type over the other. Just to make it implicitly clear, you should never use TEXT as it is proprietary and non-standard.
Why do you not use VARCHAR ( MAX ) in SQL?
Columns that are of the large object (LOB) data types ntext, text, varchar (max), nvarchar (max), varbinary (max), xml, or image cannot be specified as key columns for an index. If you want to cripple performance, use nvarchar for everything.
Why is varchar not stored out of row?
the varchar(max) will not be stored out of row unless the data stored in the row exceeds the rows limitations(which, yeah, is about 8k). Ie if you have the text “hello world” stored in a varchar max in a table with 3 columns, chances are its not going to get stored out of row. – AtaLoss Aug 22 ’11 at 1:31.
Why is varchar 255 so common on DBMS?
The historical reason behind Varchar (255) being so common (it used to be the maximum on some older DBMS), 2. Even today, it is still an limitation for some because of the index limitations discussed previously, Part 1 and 2 are not linked.