Specifies the type of data being stored (string, date, numeric, etc).
15
votes
3answers
4k views
Advantages and Disadvantages to using ENUM vs Integer types?
Lets say in some random table, you have a column named status. It's real-world values would be either enabled or disabled.
Is it better for this column's data type to be an int/bool (1 or zero) or to ...
14
votes
5answers
3k 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 ...
17
votes
7answers
5k views
How do long columns impact performance and disk usage?
In our current project it just happens too often, that we need to extend columns by a couple of characters. From varchar(20) to varchar(30) and so on.
In reality, how much does it really matter? How ...
8
votes
2answers
461 views
INT or CHAR for a Type Field
What is the best design for a table, a Type field that is of int or char(1)? In other words, given this schema:
create table Car
(
Name varchar(100) not null,
Description varchar(100) not ...
7
votes
2answers
1k views
Why does “SELECT POWER(10.0, 38.0);” throw an arithmetic overflow error?
I'm updating my IDENTITY overflow check script to account for DECIMAL and NUMERIC IDENTITY columns.
As part of the check I compute the size of the data type's range for every IDENTITY column; I use ...
11
votes
6answers
3k views
Storing IP address
I have to store the IP address of all registered users in the database. I am wondering, how many characters should I declare for such a column?
Should I support IPv6 as well? If so, what is the ...
15
votes
3answers
5k views
What are the drawbacks with using UUID or GUID as a primary key?
I would like to build a distributed system. I need to store data in databases and it would be helpful to use an UUID or a GUID as a primary key on some tables. I assume it's a drawbacks with this ...
11
votes
4answers
608 views
Does NULL have a type?
Various sources (eg Wikipedia, PSOUG) state that Oracle's null does not have a type. Is this true?
What about other RDBMSs?
11
votes
3answers
11k views
What is the difference between MySQL VARCHAR and TEXT data types?
After version 5.0.3 (which allowed VARCHAR to be 65,535 bytes and stopped truncating trailing spaces), is there any major difference between these two data types?
I was reading the list of ...
11
votes
1answer
7k views
INT(5) vs SMALLINT(5)
In MySQL table definitions is there a different between INT(5) and SMALLINT(5)? Or do they both represent the same size?
5
votes
2answers
967 views
Data type for storing an array of flags (a bitmap/bit array)
I need to store a bit array for each record of a table, supporting the following operations:
Testing if a bit is set, and setting a bit (using SQL)
Querying and setting the value using ADO 2.8 (not ...
2
votes
2answers
1k views
A Script to insert dummy Data in all tables of Database
I wanted a Script that can loop through all tables and their columns in the database and insert dummy data based on column type and size, so that i can start using the database for testing, and ...
1
vote
1answer
3k views
How can I convert from Double Precision to Bigint with PostgreSQL?
I need to convert a value of Double Precision to Bigint with PostgreSQL. How can I do that?
I have tried with to_bigint(myvalue) but that function didn't exist.
0
votes
1answer
193 views
What is the difference between int(8) and int(5) in mysql?
I found out, that if you have a field defined as INT(8) without ZEROFILL it will behave exactly as INT(5)
in both cases the maximum value is
−2,147,483,648 to 2,147,483,647, from −(2^31) to 2^31 − 1
...
