Linked Questions

7
votes
1answer
6k views

PostgreSQL list of integers separated by comma or integer array for performance?

As per subject, I have a field which is varchar in which i store some numbers separated by commas. The list grows and shrinks based on clients choices. I then use it in queries to check if a ...
5
votes
4answers
41k views

Join with comma separated values in SQL Server

I have a table [CourseMaster] LIKE CourseId CourseName ----------------------- 01 ABC 02 DEF 03 GHI 04 JKL 05 MNO 06 PQR 07 ...
3
votes
1answer
125 views

Does combining columns into 1 column helps to optimize a large table?

I have user, items and user_items tables, and as usual user has many items. Tables contains: User: ~50K Items: ~3.5M UserItems: ~5M I am using MySQL and most of my queries are selecting items of a ...
3
votes
2answers
283 views

Both Primary and Foreign Key Needed on Table?

Someone recently asked this question: There are two tables: Deal and DealCategories. One deal can have many deal categories. So the proper way should be to make a table called DealCategories ...
3
votes
1answer
159 views

which design better when use foreign key instead of a string to store a list of id [duplicate]

Possible Duplicate: Is using multiple foreign keys seperated by commas wrong, and if so, why? I'm building online examination system. I have designed to table, Question and GeneralExam. The table ...
2
votes
1answer
1k views

select items with one or more specified tags

I have two tables. One table holds tags: CREATE TABLE `tags` ( `id` int NOT NULL AUTO_INCREMENT PRIMARY KEY, `name` varchar(30) NOT NULL ) COMMENT=''; INSERT INTO `tags` (`id`, `name`) VALUES (1, ...
2
votes
0answers
20 views

Storing rows vs unique column values

I have a postgres database that has the following structure: where the fields in column1 and column2 can take any value and where the order column indicates the order in which the original data was ...
1
vote
1answer
62 views

Joining on a M-N lookup table vs keyword searching a single column

I am in the process of writing an image gallery webapp similar to that of Danbooru, and in the process, decided to take a look at danbooru's database schema for an idea about how things are structured....
1
vote
1answer
292 views

A many-to-many relationship

I'm designing a simple database and have a question regarding a relationship. So far, I have users, books, highlights and bookmarks. The relationship rules are as follows: Each user may 'subscribe' ...
1
vote
0answers
442 views

What are the pros and cons of storing two values in an array instead of two columns?

I have a project that plans to store an away team and a home team. I'm wondering if it is better to store the teams in a single array column like this: {Harvard,Colorado} Or create away_team and ...
1
vote
1answer
593 views

Database denormalization: multiple rows into single column. How bad is it? [duplicate]

We have few join-heavy queries to our SQL Server 2008 database and in an attempt to optimize them I thought of having a view that would produce this OrderID Number Traveller 1 102 ...
0
votes
3answers
3k views

Not getting the expected result with 'IN' and subquery

I am trying to access the ring_to_number from tbl_destinations that holds all the numbers. And field destinations has the comma separated ID like 1,3. but according to this query i just get the the ...
0
votes
2answers
832 views

Check and Retrieve those results where a cell(row) contains atleast one value from many values in a column [duplicate]

Let me give you an example : I have a table (name = posts) which contains following rows: id | title | .... | names 1 | . | . | . | . | . | 4 |...