So I'm kind of stumped.
I have a MySql project that involves a database table that is being manipulated and altered by scripts on a regular basis. This isn't so unusual, but I need to automate a script to run (after hours, when changes aren't happening) that would save the result of the following:
SHOW CREATE TABLE [table-name];
This command generates the ready-to-run script that would create the (empty) table in it's current state.
In SqlWorkbench and Navicat it displays the result of this SHOW command in a field in a result set, as if it was the result of a SELECT statement.
Ideally, I want to take into a variable in a procedure, and change the table name; adding a '-mm-dd-yyyy' to end of it, so I could show the day-to-day changes in the table schema on an active server.
However, I can't seem to be able to do that. Unlike a Select result set, I can't use it like that. I can't get it in a variable, or save it to a temporary, or physical table or anything. I even tried to return this as a value in a function, from which I got the error that a function cannot return a result set - which explains why it's displayed like one in the db clients.
I suspect that this is a security thing in MySql? If so, I can totally understand why and see the dangers exposed to a hacker, but this isn't a public-facing box at all, and I have full root/admin access to it. Hopefully somebody has already tackled this problem before.
This is on MySql 8, btw.
[Edit] After my first initial comments, I need to add; I'm not concerned about the data with this question whatsoever, but rather just these schema changes.
What I'd really -like- to do is this:
SELECT `Create Table` FROM ( SHOW CREATE TABLE carts )
But this seems to be mixing apples and oranges, as SHOW and SELECT aren't created equal, although they both seem to return the same sort of object
You cannot do it in the MySQL stored procedure language.
https://dev.mysql.com/doc/refman/8.0/en/show.html says:
Many MySQL APIs (such as PHP) enable you to treat the result returned from a SHOW statement as you would a result set from a SELECT; see Chapter 29, Connectors and APIs, or your API documentation for more information. In addition, you can work in SQL with results from queries on tables in the INFORMATION_SCHEMA database, which you cannot easily do with results from SHOW statements. See Chapter 26, INFORMATION_SCHEMA Tables.
What is absent from this paragraph is any mention of treating the results of SHOW commands like the results of SELECT queries in other contexts. There is no support for setting a variable to the result of a SHOW command, or using INTO, or running SHOW in a subquery.
So you can capture the result returned by a SHOW command in a client programming language (Java, Python, PHP, etc.), and I suggest you do this.
In theory, all the information used by SHOW CREATE TABLE is accessible in the INFORMATION_SCHEMA tables (mostly TABLES and COLUMNS), but formatting a complete CREATE TABLE statement is a non-trivial exercise, and I wouldn't attempt it. For one thing, there are new features in every release of MySQL, e.g. new data types and table options, etc. So even if you could come up with the right query to produce this output, in a couple of years it would be out of date and it would be a thankless code maintenance chore to update it.
The closest solution I can think of, in pure MySQL, is to regularly clone the table structure (no data), like so:
CREATE TABLE backup_20220618 LIKE my_table;
As far as I know, to get your hands on the full explicit CREATE TABLE statement, as a string, would require the use of an external tool like mysqldump which was designed specifically for that purpose.
In my project I'm using Speedment for ORM. Of course I want my code properly tested. So I decided to create an identical copy of my default database schema which I wanted to use for unit testing. In this case the name of the original schema is "project" and the name of the copy is "test_project"
My problem is that I don't know how to properly address the other database schema.
I know that, upon establishing a connection, I can use the method withSchema("test_project") to tell speedment which schema to use.
This works just fine as long as I don't have any columns identifiers in my query.
So this works:
List <User> users = userManager.stream().collect(Collectors.toList());
whereas this doesn't:
List <User> users = userManager.stream().filter(User.UID.equal(id)).collect(Collectors.toList());
It's telling me this: Unknown column 'project.User.uid' in 'where clause
I don't really understand what's going on there. (Note: I'm quite new to Speedment).
My question is: How can I access my other schema with all its rows properly addressed to it?
This was a bug in Speedment. Changing schema withSchema("test_project") is the correct way. This will be fixed in Speedment version 3.0.23.
Basically i need to know if there is any way to get the current schema name using Mybatis.
The DB engine I'm using is MySQL
The most easy way, for which you don't even need to do anything MyBatis-specific, would simply be a query:
SELECT DATABASE();
This should, according to the documentation, return the current database.
Alternatively, you should be able to get the Configuration from your SqlSession via getConfiguration() and get it from there somewhere, perhaps from the environment which allows you access to the DataSource, but you will probably need some database-specific code there.
i have to build an application to manage an existing MySQL database. This database was created with MySQLworkbench and some useful comments were added to its tables and columns.
I think it would be great to somehow, query that comments and show them to the user to explain "what that field is". The problem is i don't know if its possible to retrieve that comments (they are only visible from the workbench).
EDIT:
in the MySQL existing database i have to work with there is no INFORMATION_SCHEMA table. I think is something usual to find it but in my model there is no :S
Try with:
SELECT column_comment FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME='table_name';
You can parse the output of
show create table `YOURTABLE`;
Just wondered if there was a secret to do something like Database.Security.Users like AdventureWorks DB is setup. Seems no matter what I do to try to setup "Security.Users", I always get the dbo in front of it and have a hell of a time in C# accessing the info. Am I doing something wrong?
Are you trying to create an object called Security.Users with a dot? (as opposed to Users in the Security schema?) That's probably best avoided as you're seeing, but if you are then the best way to quote the name is probably in square brackets, i.e. [Security.Users].
dbo is the default database schema name. Unless you've configured a different default schema for your users etc. you can usually just ignore it, although it's still needed if you're referencing another database by name.
you first need to create a schema and make that schema the default schema for that user. Examples and more info can be found here: http://msdn.microsoft.com/en-us/library/ms190387.aspx
If you are using the Wizard to create this, you will always get it. Write the SQL statements and you should be fine.