Tagged Questions

1
vote
1answer
26 views

Column of generic/variable type?

In SQL, I would like to create a table which can contain generic data types. This types can change from every row. The solution I could come up to is: CREATE TABLE TagValue ( tag VARCHAR(64), ...
0
votes
2answers
26 views

Should numeric identifiers like serial numbers be stored as integers?

Many of our databases store numeric tracking codes (like serial numbers) as integers. There is little chance of these codes every getting alphabetic characters, but it still seems like an incorrect ...
20
votes
6answers
1k views

In what data type should I store an email address in database?

I understand that an 254 character email address is valid, but implementations I have researched tend to use a varchar(60) to varchar(80) or equivalent. For example: this SQL Server recommendation ...
0
votes
2answers
59 views

Adding a bool column; tracking untouched vs. false

[backstory] I have a simple database of our current Widget inventory. It averages just dozen columns across five or six tables, but has a huge number of records already. Some Widgets came with ...
0
votes
0answers
32 views

“Related search” trick in huge Hypertable database?

Several years ago, I've created search engine using PHP with MySQL (MyISAM) The "Related search" pick 5 most similar search title. The data has growing bigger in matter of days. Each submission has ...
2
votes
1answer
112 views

Storing IPv4 and IPv6 hosts and networks

I have to store the IPv4/v6 address and networks(CIDR notation) in a MySQL database. Unfortunately, I am constrained to use Mysql. So, I'm looking for the equivalent of the inet type of PostgreSql. ...
2
votes
1answer
172 views

SQL Server - storing ulong as primary key

I need to store ulong values as a primary key in SQL Server. Since SQL Server doesn't have a ulong datatype (or for that matter anything unsigned), the only way to go is to have column as ...
0
votes
2answers
78 views

looping through a table type variable

I have a function that has one parameter of a table type, i want to loop through all the fields and return the column that has a null or empty value. CREATE OR REPLACE FUNCTION ...
0
votes
1answer
225 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 ...
7
votes
3answers
478 views

What should I use? A string or 15 integer fields?

I am developing a student tracking program where I need to store 15 exam marks. I can store the marks as a string and split them up when I need to, for purposes such as performing arithmetical ...
3
votes
1answer
495 views

Designing a user authenication (Roles & Rights) module

I am trying to model a User Authentication module for a MS SQL Server database that will be the back end to a Delphi UI Application. Basically, I want to have user accounts where the user belongs to ...
4
votes
1answer
132 views

How to set constraints on UDT in SQL Server 2005 - 2012

I'm creating my UDT: CREATE TYPE [dbo].[Code] FROM VARCHAR(20) NOT NULL As RULES and DEFAULTS are considered deprecated, what is the recommended way to set constraint on my type to make sure that ...
2
votes
2answers
606 views

What is the best identifier for a UserID? 64 bit integers, UUID V5, or 64 character SHA256 UID?

I wish to future-proof my application. What is the best type of identifier to use? I am considering: 64 bit Integer UUID 64 character SHA256 I am not developing a distributed system, so is ...
2
votes
4answers
746 views

Best pratice to store dates group by months-year key par value

I am making one service which needs to hold data grouped and calculated by year-month combination. I know how to calculate data and put it on new table. But I am confused what kind of data type I ...
4
votes
1answer
1k views

Storing XML in varchar(MAX) or use SQL-XML

I am defining a schema for a new set of resources using SQL Server 2008... In this case, each record (e.g. row) will need to store XML fragments. From time-to-time; although not frequently; I'll need ...
8
votes
2answers
519 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 ...
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 ...
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 ...
11
votes
6answers
4k 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 ...
3
votes
3answers
1k views

Estimate large database size and speed

First I want to know how to estimate the database size regarding the biggest table it will contains. I've the following : +----------+------------------+------+-----+---------+-------+ | Field | ...
11
votes
3answers
12k 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 ...