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Questions tagged [mysql]

All versions of MySQL (not Microsoft SQL Server). Please also add a version-specific tag like mysql-5.7 if that is relevant to the question.

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7
votes
1answer
3k views

What's the maximum number of tables that can be referenced in a query in MySQL?

In the days of SQL Server 2000 and 2005, the maximum number of tables in a query was 256. Does MySQL have a similar limitation? I know that such query of such size means that either there's ...
4
votes
1answer
379 views

Using CoreData on a client-side application

This may be a bit more of an SO question, but... If I'm writing a client-side application for OS X that's going to sync with an online MySQL database, is there any difference on if I have CD use ...
31
votes
4answers
49k views

How can I change the default storage engine in phpmyadmin?

I use InnoDB almost exclusively in my applications. However, if I'm not careful when setting up the table, I forget to change it and phpmyadmin sticks me with MyISAM. Is there a way to change the ...
18
votes
6answers
364 views

Securing DB passwords

Looking at the structure of most PHP/MySQL-based websites I've seen, it appears that it's not terribly difficult to discern the database password if you dig a bit, as there's invariably a setup or ...
8
votes
3answers
339 views

What does the output of a JOIN statement look like?

I've been wanting to use joins for a while, but I'm having trouble visualizing the output so I know how to put it to use. Let's say I have 2 tables: CREATE TABLE Cities ( id INT UNSIGNED PRIMARY ...
8
votes
3answers
2k views

MySQL LDAP authentication

Is LDAP authentication and authorization in MySQL possible? What are the requirements (MySQL version, third-party software etc.)? How it's organized? Thanks.
7
votes
6answers
2k views

Alternative Database Tools for Web Admin [closed]

I currently use phpmyadmin for most of my database administration. It works well enough, but I'm interested in other tools that might work more quickly/efficiently/etc... What are the best and/or ...
41
votes
2answers
19k views

NULL or NOT NULL by default?

In MySQL, is it better to always allow nulls unless you know a field is required, or always use Not Null unless you know a field will contain nulls? Or doesn't it matter? I know in some DBMSs they ...
25
votes
6answers
16k views

How to create a conditional index in MySQL?

How to create an index to filter a specific range or subset of the table in MySQL? AFAIK it's impossible to create directly but I think it's possible to simulate this feature. Example: I want to ...
12
votes
5answers
8k views

Are there any MySQL Benchmarking tools? [closed]

I've heard a long time ago that there is this tool that helps you tweek mysql settings for better performance but i can't seam to find it. I am aware that I can use ab for apache to simulate high ...
28
votes
5answers
60k views

Where can I find the mysql slow log?

Just as the title says, where can I see it ? Are there any config options for it ( like how many ms would determine if a query is slow or not ) ?
192
votes
7answers
247k views

How can I optimize a mysqldump of a large database?

I have a symfony application with an InnoDB database that is ~2GB with 57 tables. The majority of the size of the database resides in a single table (~1.2GB). I am currently using mysqldump to ...
38
votes
5answers
6k views

When is the right time to use MariaDB instead of MySQL, and Why?

What we earn and what we lost with this migration? What should I expect as drawbacks after the migration? Is it really unnecessary to change the applications in any situation?
68
votes
5answers
11k views

How can a group track database schema changes?

What version control methodologies help teams of people track database schema changes?
262
votes
10answers
266k views

What are the main differences between InnoDB and MyISAM?

What are the main differences between InnoDB and MyISAM?
5
votes
3answers
2k views

With MySQL Replication, what level of resilience is possible?

I've found lots of good material on setting up MySQL replication, but not much on what to do in the event of failures. Understanding the degree of resilience I can achieve is fundamental to designing ...
7
votes
4answers
13k views

How to do a mysqldump with a use database in the dump

So the command I normally use to get a database sent to another server is: mysqldump -u user -p --add-drop-tables database *file* But I always have to go into the file and add a line at the top: use ...
3
votes
4answers
15k views

In MySQL Workbench, insert a new column at the “top” of a table?

I must keep a table's columns as specified in a specification that changes quite often. In MySQL Workbench, adding a new columns after all the others is easy, but I can't find a way to insert a new ...
2
votes
1answer
3k views

MySQL : “FLUSH TABLES WITH READ LOCK” started automatically

I would like to understand how this happened. I was running a query that would take a long time, but should not lock up any table. However, my dbs were practically down - it seems like it was being ...
41
votes
8answers
223k views

MySQL DB import/export command line in Windows

How to export / import a database in MySQL through the command line? MySQL system configuration, WampServer server installed. OS: Windows The advice for my local host, not an live hosting...
11
votes
9answers
12k views

Load-balanced MySQL cluster without load balancer

I'm looking to create a load-balanced MySQL cluster, but without the actual load-balancer, in order not to add another point of failure or complexity. What I was thinking was to have the following: ...
45
votes
9answers
29k views

Is there a tool like Microsoft's “SQL Server Profiler” for MySQL? [closed]

While developing on MySQL I really miss being able to fire up a profiler. I find SQLyog is a good enough replacement for Query Analyzer but have not found a tool that works like SQL profiler. For ...
74
votes
7answers
154k views

How do I completely disable MySQL replication

I am running dual master MySQL replication and now want to move to a single database with no replication. How do I completely disable replication on both databases?

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