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Mar
19
comment big db for managing user files and settings
That is not even close to following to the relational model. If you intend to implement this in MySQL, you certainly aren't going to want millions of tables, all but one of them with one record each. You shouldn't have any issue with the three tables in my answer, each having millions of records each.
Mar
19
comment big db for managing user files and settings
Per-user tables? So adding a new user means adding two new tables?
Mar
19
comment Best relational database structure for this data
I'm not convinced that Roles_Applications is a real thing. Given that all permissions are application-specific, it seems there are Applications_Permissions (what you have labeled Permissions), which may then be assigned to specific roles via a record in Applications_Permissions_Roles. Roles_Applications, in fact, seems to be describing the most basic application permission--simple access. Or, it is asserting that a role has some level of permissions for an application, but you have to look elsewhere to determine which ones.
Mar
19
comment big db for managing user files and settings
Three separate databases? No, I wouldn't do that. I would just use the three tables above in a single database.
Mar
18
comment Best relational database structure for this data
I'm not sure I've wrapped my mind around the interplay of roles, applications, and permissions. Each role/application has a specific permission that is independent of a role's other applications? For example, a CEO/Topdesk might have only read permission, while a CEO/Calendar might have write?
Mar
18
revised how to set a row's value from a certain row's value?
added per first comment
Mar
18
answered big db for managing user files and settings
Mar
18
answered how to set a row's value from a certain row's value?
Mar
8
answered Update Table A row if Table B row is changed
Mar
8
comment Does this query make sense?
I believe you are correct. I jumped to the conclusion that the first was correct because that way the query makes sense. If the behavior really is MAX(start_date) OVER (PARTITION BY person_id) then the original query seems to be just a tortuous way of getting DISTINCT person_id for that group in the table.
Mar
7
comment Does this query make sense?
Ah yes, there could be multiple people sharing the honor of having started leave most recently of those in Group 146.
Mar
7
answered Does this query make sense?
Mar
3
comment MySQL design problem
"Nonsense, I say. Disregard that advice." I second that. I would be be very suspect of any advice that comes from whatever source offered you that little nugget of absurdity. Much better advice is to completely disallow direct access to tables, using stored procedures as the only interface to them.
Feb
20
comment Database Design Cars-Models / Car Classifieds
If this is what you were looking for, perhaps you might accept it as the answer. Otherwise I'd be more than happy to expound on it if more is needed.
Feb
19
answered Database Design Cars-Models / Car Classifieds
Feb
5
comment MySQL Tables crashing randomly
Corruption can cause mysqld to crash, which can cause further corruption, so yes. It is theoretically possible for a bug in the data storage code that results in certain queries causing a crash, per the MySQL troubleshooting docs.
Feb
4
comment MySQL Tables crashing randomly
It's hard to say from the info given. Crashes can cause corruption, and corruption can cause crashes. All we have is evidence of one crash. It is not likely that it is a bug, but it is possible. If you follow the steps above to try to isolate a query that is causing a crash, and you can replicate that crash reliably, it's almost certainly a bug and should be submitted.
Feb
4
comment MySQL Tables crashing randomly
It may be that I am being overly cautious, but in the event that you somehow have an actual bug in your version of mysqld, I would try to bypass it in verifying that your tables are starting up uncorrupted by cutting it out. Since mysqlcheck is basically just an interface to mysqld, invoking mysqlcheck would also potentially be invoking the bug. It's not very likely, but it is a possibility.
Feb
4
comment MySQL Tables crashing randomly
A single instance can have multiple threads, which is what I assume htop is showing you. If top shows only one mysqld running, you have only one instance running.
Feb
2
comment MySQL Tables crashing randomly
By multiple instances I mean more than one mysqld process running concurrently. The biggest difference between mysqlcheck and myisamchk is that mysqlcheck is a client application that sends requests through the MySQL server, so it requires mysqld to be running in order to function. myisamchk is a utility that operates directly on the files--it's best if mysqld is NOT running. If you use myisamchk, you can verify integrity before starting mysqld--I thought that might eliminate one more variable in the troubleshooting process.