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What is a proper naming convention for MySQL FKs?
Being that they must be unique, what should I name FK's in a MySQL DB?
4 Answers
4
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Possible to do a MySQL foreign key to one of two possible tables?
...problem I have three tables; regions, countries, states. Countries can be inside of regions, states can be inside of regions. Regions are the top of the food chain.
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MySQL select 10 random rows from 600K rows fast
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A great post handling several cases, from simple, to gaps, to non-uniform with gaps.
http://jan.kneschke.de/projects/mysql/order-by-rand/
For most general case, here is how you do it:
SELECT name
FROM random AS r1 JOIN
(SELECT CEIL...
ORDER BY the IN value list
I have a simple SQL query in PostgreSQL 8.3 that grabs a bunch of comments. I provide a sorted list of values to the IN construct in the WHERE clause:
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scopes with lambda and arguments in Rails 4 style?
I'm wondering how the following is done in Rails 4 or if I just use the Rails 3 approach for using a lambda that can pass an argument the same way with 4 as I do with 3.
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Django filter queryset __in for *every* item in list
Let's say I have the following models
6 Answers
6
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When to add what indexes in a table in Rails
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Should I add "index" to all the foreign keys like "xxx_id"?
It would be better, because it accelerates the search in sorting in this column. And Foreign keys are something searched for a lot.
Since Version 5 of rails the index will be c...
MySQL JOIN the most recent row only?
...changes made to the customer, i.e. when there's a change made a new row is inserted.
8 Answers
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How to check which locks are held on a table
How can we check which database locks are applied on which rows against a query batch?
6 Answers
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How to create a MySQL hierarchical recursive query
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For MySQL 8+: use the recursive with syntax.
For MySQL 5.x: use inline variables, path IDs, or self-joins.
MySQL 8+
with recursive cte (id, name, parent_id) as (
select id,
name,
parent_id
from products
where parent_id = 19
union all
se...