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Query to count the number of tables I have in MySQL
I am growing the number of tables I have and I am sometimes curious just to do a quick command line query to count the number of tables in my database. Is that possible? If so, what is the query?
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Deleting all records in a database table
How do I delete all records in one of my database tables in a Ruby on Rails app?
7 Answers
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Mysql error 1452 - Cannot add or update a child row: a foreign key constraint fails
... having a bit of a strange problem. I'm trying to add a foreign key to one table that references another, but it is failing for some reason. With my limited knowledge of MySQL, the only thing that could possibly be suspect is that there is a foreign key on a different table referencing the one I am ...
MySQL: Fastest way to count number of rows
...eyword after SELECT:
SELECT SQL_CALC_FOUND_ROWS [needed fields or *] FROM table LIMIT 20 OFFSET 0;
After you have selected needed rows, you can get the count with this single query:
SELECT FOUND_ROWS();
FOUND_ROWS() has to be called immediately after the data selecting query.
In conclusion,...
How to use php serialize() and unserialize()
...p script ready to store/send it somewhere. You have the option to create a table that exactly matches the expected data, but this is tedious you are essentially doubling your work load because you have to write code that matches too, plus changes in database need changes in code or vice versa. When ...
Twitter bootstrap scrollable table
I would like to have a table on my website. The problem is that this table will have about 400 lines. How can I limit the table's height, and apply scrollbar to it?
This is my code:
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How do you effectively model inheritance in a database?
...database. Which you choose depends on your needs. Here are a few options:
Table-Per-Type (TPT)
Each class has its own table. The base class has all the base class elements in it, and each class which derives from it has its own table, with a primary key which is also a foreign key to the base clas...
Select n random rows from SQL Server table
I've got a SQL Server table with about 50,000 rows in it. I want to select about 5,000 of those rows at random. I've thought of a complicated way, creating a temp table with a "random number" column, copying my table into that, looping through the temp table and updating each row with RAND() , and ...
What GRANT USAGE ON SCHEMA exactly do?
...chema within. Similiarly, GRANTing on a schema doesn't grant rights on the tables within.
If you have rights to SELECT from a table, but not the right to see it in the schema that contains it then you can't access the table.
The rights tests are done in order:
Do you have `USAGE` on the schema?...
Best design for a changelog / auditing database table? [closed]
I need to create a database table to store different change log/auditing
(when something was added, deleted, modified, etc). I don't need to store particularly detailed info, so I was thinking something along the lines of:
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