I have a stored procedure which basically selects data from one table and insert into another table. Basically I am doing data archiving manually. Now, I want to write an event just like discussed here
However, after reading that post and researching online, I came to know that it's not possible to create an event inside a stored procedure. Is there a way to accomplish my goal in MySQLWorkbench?
I believe you are thinking this in the oposite direction: You can't create an event in a stored procedure, but you can create a stored procedure and call it from an event.
Example:
delimiter $$
create procedure myProc()
-- Dummy procedure to move the data from mainTable to backupTable,
-- and then clear (truncate) mainTable
begin
insert into backupTable select * from mainTable;
truncate mainTable;
end $$
delimiter ;
-- Now, suposing that you want to execute this procedure every hour:
delimiter $$
create event myEvent
on schedule every 1 hour
do
begin
call myProc();
end $$
delimiter ;
You can write this as any other query in the workbench, or directly in the command line client.
About your concern
After reading your comment, I believe you are a bit confused about what MySQL Workbench is.
MySQL Workbench is only a graphical application that allows you to connect to a MySQL server and perform queries and administration tasks. But Workbench is not the core of MySQL... it is only a viewer (with steroids, maybe, but a viewer after all).
Now, the event scheduler does not reside in Workbench, but in the MySQL server instance you are connecting to. Just as the tables, views, procedures and functions are not stored in the Workbench interface but in the server, the events are also stored in the server.
(Yes, I believe it is a relevant SNAFU that the scheduled events don't show anywhere in the graphical interface, but... after a while, one learns to live with that kind of frustrations and to move on with life)
Maybe your only concern is: "Hey, and what if I want to know what events are set to run in the event scheduler?" You can execute a "show events" query to show a list of the events in the current database, and you can execute "show create event yourEvent" to show the create event syntax for that event.
I insist: Read the manual, and keep a copy at hand (download the manual for your MySQL version here).
Related
I need to call bash script when mysql database schema has changed. As example queries:
ALTER TABLE, CREATE TABLE, DROP TABLE
it possible?
Don't think that's possible any way. You could have probably use a DDL Trigger but MySQL doesn't support one. See worklog https://dev.mysql.com/worklog/task/?id=2418.
Though you can write a stored procedure to perform the business logic and call that procedure but capturing the DDL event isn't possible AFAIK. You should also check on Event Scheduler in MySQL
I need to use user variable in prepare statement of mysql
stored procedure. (The purpose is to substitute the table name in
drop table command, which is unable to be injected via ? and
passed via execute using... statement because it is not a data element).
I suppose the user variables are session-wide global variables.
I suppose the stored procedure accessing the user variable must be
synchronized to protect against unwanted behaviour when it is called
simultaneously more times within single session (which I cannot prevent).
How to perform such synchronization?
Is there any chance it is performed internally by the mysql?
It seems like mysql get_lock() & co. uses logic that does not help much:
get_lock('a') followed by get_lock('b') destroys state of a. Maybe I have terribly missed some point here...
For those who would ask the "what exactly would you like to do" question:
drop procedure if exists drop_t_table; delimiter $$
create procedure drop_t_table(in in_t_table_name varchar(128))
begin
declare sql_drop varchar(256) default 'drop temporary table if exists ';
--
-- I would suspect sql_drop_table user variable guard should be locked here...
--
set #sql_drop_table = concat(sql_drop, in_t_table_name);
--
-- What if the procedure is preempted to another call here
-- and the sql_drop_table gets different table name?
--
prepare exe from #sql_drop_table;
--
-- ...and unlocked here
--
execute exe;
deallocate prepare exe;
end$$ delimiter ;
Variables declared within your stored procedure are local to the procedure. An example is sql_drop in your code.
Each session is, basically, single-threaded. You can't do more than one thing at a time within a session. There's no way to call a stored procedure more than once from within a particular session.
If you have more than one session you can call the same stored procedure from both of them. But, a DROP TABLE operation is basically idempotent: If you call it more than once, it has the same effect as calling it just once. It isn't precisely idempotent: it throws an error if the table doesn't exist. But, still, dropping the same table more than once isn't any more destructive than dropping it once.
Temporary tables (a) are only visible to the session that created them, and (b) vanish when the session ends. So, going to a lot of trouble to drop them explicitly might be overkill.
So, with respect, you might be overthinking this problem.
I have created a procedure in mysql having multiple select statements in it.
Here is my code :
DELIMITER $$
USE `databasename`$$
DROP PROCEDURE IF EXISTS `wholeProjectDetails`$$
CREATE DEFINER=`databasename`#`localhost` PROCEDURE `wholeProjectDetails`(IN givenpid INT)
BEGIN
select * from projects where projectid=givenpid;
select * from projects where projectid<>givenpid;
END$$
DELIMITER ;
When i called this procedure using statement :
call wholeProjectDetails(2);
it is displaying only first statement's results, i want that it will display both statement's records.
Please let me know what i am doing wrong?
Thanks
When you call this procedure, MySQL creates two result-sets. Now, you need to get these two result-sets using your MySQL client. Read information about client you use, does it support this feature? For example, in .NET you can use IDataReader.NextResult Method, in mysqli - mysqli::next_result function, and so on.
If you want just to view these result-sets, you can install one of MySQL GUI tools, there are free ones.
I am using SQL Server 2008. I have stored procedure, which (on some conditions) insert data in my table, this stored procedure will be call from application each time when my window opens. SQL Profiler shows it like below
exec TEST.dbo.spInsertRecords #parameter
Now what I want is to fire a trigger whenever this stored procedure will be call to execute.
Is it possible? If yes please share the syntax example.
Triggers are set on tables, if you really need something triggered upon calling your procedure (i honestly cannot see why since you shall be able to modify the procedure to do whatever behaviour you'd want), add some dummy table (a log table ?) , create your trigger on that table (on insert for example), and "trigger" the trigger inside your procedure (insert a row).
If the trigger is expected to execute some code, for example writing record into a log.
Write the code directly into the procedure.
If you want to execute universal code before or after all procedures, write the code in the place where the procedure is executed.
For example in PHP:
odbc_exec("execute my_trigger_before '$procedure_name' #parameters;
execute $procedure_name #parameters;
execute my_trigger_after '$procedure_name' #parameters;")
I'm messing around with stored procedures for the first time, but can't even create a simple select! I'm using phpMyAdmin and this is my SQL:
DELIMITER //
CREATE PROCEDURE test_select()
BEGIN
SELECT * FROM products LIMIT 10;
END //
DELIMITER ;
After submitting that, my localhost does some thinking for a loooong time and eventually loads a page with no content called /phpmyadmin/import.php. After reloading phpMyAdmin and trying to invoke the procedure:
CALL test_select();
I get a "PROCEDURE doesn't exist" error. Any ideas?
Try to use the delimiter field of phpMyAdmin, as shown in the screenshot below:
Simply put the following in the query window:
CREATE PROCEDURE test_select()
BEGIN
SELECT * FROM products LIMIT 10;
END
In addition note that there is bug in some older versions of phpMyAdmin, which can cause an error when you call stored procedures that contain SELECT statements from phpMyAdmin.
You may want to check out the following posts for further reading:
MySQL Stored Procedures not working with SELECT (basic question)
How do I write an SP in phpMyAdmin (MySQL)?
This bug effects only phpMyAdmin, and you would still be able to call the stored procedure from anywhere else.