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Advantages and disadvantages of GUID / UUID database keys
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@Matt Sheppard:
Say you have a table of customers. Surely you don't want a customer to exist in the table more than once, or lots of confusion will happen throughout your sales and logistics departments (especially if the multiple rows about the customer c...
How to get the top 10 values in postgresql?
... *,
rank() over (order by some_value_column desc) as my_rank
from mytable) subquery
where my_rank <= 10
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Why is a “GRANT USAGE” created the first time I grant a user privileges?
...e MySQL server, hence USAGE. It corresponds to a row in the `mysql`.`user` table with no privileges set.
The IDENTIFIED BY clause indicates that a password is set for that user. How do we know a user is who they say they are? They identify themselves by sending the correct password for their accoun...
What is the best way to stop people hacking the PHP-based highscore table of a Flash game
...both these conditions are true, it writes the high score to the high score table and returns a signed "success" message to the client. It also removes the salt value from the pending query list.
Please keep in mind that the security of any of the above techniques is compromised if the shared secr...
Best Practices: Salting & peppering passwords?
...n order for it to be considered secure. Additionally, it has to be implementable in a maintainable way. The most secure system that can't be maintained is considered insecure (because if any part of that security breaks down, the entire system falls apart).
And peppers fit neither the provable or t...
Detect if value is number in MySQL
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This should work in most cases.
SELECT * FROM myTable WHERE concat('',col1 * 1) = col1
It doesn't work for non-standard numbers like
1e4
1.2e5
123. (trailing decimal)
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How can I get around MySQL Errcode 13 with SELECT INTO OUTFILE?
I am trying to dump the contents of a table to a csv file using a MySQL SELECT INTO OUTFILE statement. If I do:
13 Answers...
JPA: what is the proper pattern for iterating over large result sets?
Let's say I have a table with millions of rows. Using JPA, what's the proper way to iterate over a query against that table, such that I don't have all an in-memory List with millions of objects?
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Postgresql query between date ranges
...= 2
This involves calculating the conditions for every single row in the table (a scan) and not using index to find the range of rows that will match (a range-seek).
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Are Stored Procedures more efficient, in general, than inline statements on modern RDBMS's? [duplica
...at is generated is sub-optimal.
For example, if you send SELECT *
FROM table WHERE id BETWEEN 1 AND
99999999, the DBMS may select a
full-table scan instead of an index
scan because you're grabbing every row
in the table (so sayeth the
statistics). If this is the cached
version, then ...