The clarity of your voice and explanations make your tutorials enjoyable to watch. Which is something I never thought I'd say for SQL tutorials !
@ailomarkcristobal.delacruz92222 жыл бұрын
you clear the lessons for 10 minutes which i get difficult to undrstand when i listened to my teacher, thank you so much sir
@joshwzr1257 Жыл бұрын
just this is enough to the point I wanted it to be. Lemme watch others i.e. stored procedure as this was the first video to land on on a right teacher like you
@jordanscarrott37495 жыл бұрын
This video is really good. Thanks for making this. It helps just having someone walk through an example and I like that you explained the reasoning for each piece of the code that you wrote. Have a good day
@mr_santaclauss28403 жыл бұрын
One of the greatest tutorial video, super easy to understand. Give you a sub because of names in your table, the real man of cultures!
@MaryanaDaniv3 жыл бұрын
Your voice is truly melodic! Thank you for your explanation!!!
@raju36288 ай бұрын
Thank you so much sir, got more information about the triggers in 10 minute videos
@NJhansisri2 жыл бұрын
Learning is easy with right teachers ☺️, I am glad to hear this lecture.
@jayeshrao30333 жыл бұрын
Thanks, Steve, I just realized I should have been creating triggers all this while to prevent inconsistent data in the tables.
@siddharthshekhawat55022 жыл бұрын
Great job Steve 👍 love from India ,read this topic in my computer science graduation and still not understand it ,,,,like what a learned today,,,so thanks 🙏
@AvinashKumar-ps4tw2 жыл бұрын
Thanks for sharing crips and crystal clear concepts.
@starmovie52255 жыл бұрын
All your tutorials are very helpful, i always learn something new from your videos. Keep it up!
@arianseyedi3 жыл бұрын
You're an amazing teacher. Thanks for contributing
@urospopovic77564 жыл бұрын
Thank you! Clear and simple to the point.
@LuciaSilva-ek3qr3 жыл бұрын
Great job! Very easy to understand your explanation. Thank you so much!
@hitesh-patil3 жыл бұрын
I understood trigger now. Thank you so much. 👍
@coder40602 жыл бұрын
Much appreciated, very clear and well paced lesson
@kheireddine78894 жыл бұрын
brief and simple explanation ,make it perfect thanks a lot :)
@pratham57464 жыл бұрын
Thank u so Much , definitely will recommend it To A friend
@michaell17874 жыл бұрын
If only the trigger problems were this easy in my college class. Mine are more like "Create a trigger named trg_char_hours that automatically updates the AIRCRAFT table when a new CHARTER row is added. Use the CHARTER table’s CHAR_HOURS_FLOWN to update the AIRCRAFT table’s AC_TTAF, AC_TTEL, and AC_TTER values."
@dnngyn3 жыл бұрын
omg the aircrafts question, my class as well
@GreenSlugg2 жыл бұрын
I appreciate the video, but I was hoping for a more practical example. Something like if a new row is added to employee, then automatically add the next employee ID in the sequence.
@SteveGriffith-Prof3ssorSt3v32 жыл бұрын
Having an automatic new id is what setting your primary key column to AUTO_INCREMENT is for.
@GreenSlugg2 жыл бұрын
@@SteveGriffith-Prof3ssorSt3v3 Thank you! Keep making videos! I look forward to seeing more of them.
@samharrell51422 жыл бұрын
Thank you for such a clear and straightforward explanation! What if I am inserting 500k rows into a table using an "INSERT INTO table SELECT * FROM....", and want the trigger to return the last auto increment id value (after the insertion has taken place) is there a way to build the trigger that way? So that it is not FOR EACH ROW but instead just for the last row inserted?
@SteveGriffith-Prof3ssorSt3v32 жыл бұрын
A trigger is on every operation. Maybe consider a stored procedure
@soldadopreciso3 жыл бұрын
Thanks pal, very useful tutorial.
@misterpresident29814 жыл бұрын
excelent tutorial. Thanks a lot
@lestercutchall22752 жыл бұрын
Your videos have been providence for me! I have a question: Why is an error returned that a column doesn't exist when I try to run an "after insert" trigger while the column does exist in the database. The column is used as a filter in a "Where" clause within the trigger body. I use the same syntax not in a trigger body and it works.
@SteveGriffith-Prof3ssorSt3v32 жыл бұрын
WHERE clauses filter based on values in columns. They can't work if the column doesn't exist within the scope of the current query. The Trigger is like another query running on its own.
@bronxed36665 жыл бұрын
job well done. Thank you
@techfifer61373 жыл бұрын
Well explained..👏🏻
@kingmanzhang5 жыл бұрын
This is really great! I got puzzled during the process when you set NEW.name = UPPER(NEW.name) as I thought the latter should be OLD. It makes sense when thinking again about it, but maybe it will help to clarify.
@SteveGriffith-Prof3ssorSt3v35 жыл бұрын
We are taking the NEW value that gets passed in and converting that NEW value to uppercase. We are not touching the OLD value. We don't care about it any more. We are going to be replacing it with the NEW value.
@nameshd6583 жыл бұрын
Thanks man. Awesome!!
@thegdt374 жыл бұрын
Thank you!
@nuruhusseinmohammed41404 жыл бұрын
great explanation. One question tho. Is that possible to use a trigger with WebSockets to achieve real-time data access? eg. chat app or is there another way in addition to Graph QL subscriptions.
@SteveGriffith-Prof3ssorSt3v34 жыл бұрын
Triggers are only running within the database. They cannot trigger things to happen outside the database with your code. They can cause changes within the data, like setting a flag value in a table. Your code can check the database to see if the flag is set within the data and then decide to do something.
@nuruhusseinmohammed41404 жыл бұрын
Ok. Thanks.
@deepakkumarthangavel95742 жыл бұрын
Thanks bro it woked
@doctor91014 жыл бұрын
Sir, one question, can we make a trigger run a process in Windows, or call a method in some DLL
@SteveGriffith-Prof3ssorSt3v34 жыл бұрын
Not from MySQL. No.
@doctor91014 жыл бұрын
@@SteveGriffith-Prof3ssorSt3v3 Thanks sir for you quick reply, u have a fan here
@brijeshkanchan97764 жыл бұрын
Thank you Sir
@natnaelghirma26174 жыл бұрын
Quality tutorial man. Is it possible to interact with other databases in different servers to have the databases concurrently work?
@SteveGriffith-Prof3ssorSt3v34 жыл бұрын
If you are talking about multiple databases that are connected and sharing responsibility for the same data then that would be a cluster - dev.mysql.com/doc/mysql-cluster-excerpt/5.7/en/mysql-cluster-basics.html If you are talking about different databases storing different data then you need to use other tools / write your own code to manage that concurrently.
@natnaelghirma26174 жыл бұрын
@@SteveGriffith-Prof3ssorSt3v3 I needed clustering. Thank you for clarifying.
@ivandeninski4 жыл бұрын
Thank you
@camiloandreshernandez12343 жыл бұрын
hey Steve, thank you so much for making these videos, they're very helpful! I have a question: I have a table which has a column called "expiration date"; is there a way to make a trigger that inserts values into another column when that expiration date is close to happening? thanks for your help
@SteveGriffith-Prof3ssorSt3v33 жыл бұрын
Triggers are tied to changes made to data in a table. If you add or delete or update data in a table, then that will cause your trigger to run. Triggers don't monitor values and compare the values against some other value to run some procedure. If you want things to happen on a schedule, like checking once per day if the value in a column called "expiration date" has reach some threshold, then you need to do that outside the database. Cron tasks and similar things can run a server-side script which looks at the data and decides what to do. I would probably create a VIEW of all the expiry dates and the row ids for each item and have that view sorted/indexed by the date. The VIEW will always reflect the latest data and is an easy thing to run queries against. The result of the query can be used to update whatever you want.
@camiloandreshernandez12343 жыл бұрын
@@SteveGriffith-Prof3ssorSt3v3 thank you so much for your reply! I'll look into it; unfortunately I'm starting out with databases and such, do you happen to have any resources I may look into to get it done? Again, thank you for being such a great help!
@SteveGriffith-Prof3ssorSt3v33 жыл бұрын
@@camiloandreshernandez1234 This playlist is my only relational DB resource.
@SteveGriffith-Prof3ssorSt3v33 жыл бұрын
You might want to look into MySQL Scheduled Tasks. dev.mysql.com/doc/refman/8.0/en/events-overview.html I don't have a video on them but they might help you.
@camiloandreshernandez12343 жыл бұрын
@@SteveGriffith-Prof3ssorSt3v3 thank you so much Steve! I'll be sure to check it out :D
@artemidarobo64503 жыл бұрын
Please can you help me, why does my trigger on employee table says error you can’t create triggers on system tables?? Is employee created by me on the mysql db a system table?
@SteveGriffith-Prof3ssorSt3v33 жыл бұрын
Did you create the employee table inside one of the system databases?
@MzVixen053 жыл бұрын
Thank you!!!
@Wickedroonz4 жыл бұрын
thank you sir
@amjadgul50745 жыл бұрын
awesome man :-)
@aladoreferns9853 жыл бұрын
I'm having a trouble in implementing mysql triggers
@chanleon54083 жыл бұрын
I got the following error, when I do call procedures. SQL query: CALL char_race('Fili', 12) MySQL said: Documentation #1305 - PROCEDURE movies.char_race does not exist
@SteveGriffith-Prof3ssorSt3v33 жыл бұрын
It says that you have not created the function or stored procedure called `char_race` in your database.
@Stevie223322 жыл бұрын
I need help making a trigger when the limit of 10 is passed in a table
@SteveGriffith-Prof3ssorSt3v32 жыл бұрын
Do a trigger on insert that calls a stored procedure. The stored procedure could do things like check the number of records in the table. Here is a reference on combining triggers with stored procedures - www.mysqltutorial.org/mysql-triggers/mysql-call-stored-procedure-from-trigger/
@TheShantanu303 жыл бұрын
Hi..Is it possible to update a field of type timestamp on updation of a particular column?
@SteveGriffith-Prof3ssorSt3v33 жыл бұрын
Yes. This stackoverflow answer has a good code sample stackoverflow.com/questions/22170758/mysql-timestamp-fields-created-modified
@MrSmokedTurkey5 жыл бұрын
Is it possible to create a trigger on a table that will delete a record from the table whenever something gets inserted into it? I have to make sure that there are between 80 and 100 records in a table but every hour a new item gets inserted into it by a script. I need to use the value of whatever gets inserted last so I thought to achieve this by defining a trigger that will delete the oldest item in the table whenever something new gets inserted. However I get an error "Can't update table in stored function/trigger because it is already used by statement which invoked this stored function/trigger." Thanks in advance
@SteveGriffith-Prof3ssorSt3v35 жыл бұрын
triggers are more of a row-level thing. Delete a row and then do something with the deleted value or insert a row and do something with the inserted value - like check if it is a valid value. A trigger can access both old and new data in its own table. A trigger can also affect other tables, but it is not permitted to modify a table that is already being used (for reading or writing) by the statement that invoked the function or trigger. I would suggest creating a stored procedure that you can run from your server-side code each time you do an insert. OR Call the stored procedure from the Trigger. Here is a quick reference for doing this - www.mysqltutorial.org/mysql-triggers/mysql-call-stored-procedure-from-trigger/ OR Create an Event that runs on a schedule - dev.mysql.com/doc/refman/5.7/en/create-event.html - like a scheduled task that checks the size of the table once an hour and
@MrSmokedTurkey5 жыл бұрын
@@SteveGriffith-Prof3ssorSt3v3 thanks for the quick reply, I went with the event scheduler. Didnt know this existed, thanks alot!
@CC-vj6dd4 жыл бұрын
I need to create a trigger that sets/creates an automatic order (in a second table), whenever the stock of that product (in a 1st table) gets to zero. Any ideas, please? Ty!
@SteveGriffith-Prof3ssorSt3v34 жыл бұрын
Triggers only run on the table where they were created. They can't cause a change in another table. However, if you call a stored procedure instead of just an UPDATE command, then you can use the trigger to set a value in a variable like in this example - dev.mysql.com/doc/refman/5.7/en/trigger-syntax.html - and then, in the Stored Procedure, run your next SQL command too update the other table.
@CC-vj6dd4 жыл бұрын
@@SteveGriffith-Prof3ssorSt3v3 Wow! Thank you so much! You're awesome!
@MeshTheSnake5 жыл бұрын
When I try to use the github sql file to create the tables in Oracle SQL I keep getting this error 'identifiers may not start with any ASCII character other than letters and numbers.' I think it may be due to all the back ticks you have in the file but I'm not 100% sure. Any help is appreciated.
@SteveGriffith-Prof3ssorSt3v35 жыл бұрын
Oracle, msaccess, SQL server, mysql, etc. they all have minor differences in what characters they use and slight variations in their version of SQL. Sometime * is a wildcard. Sometimes % is the wildcard. Sometimes you need to use double quotes and sometimes not. Backticks work for some but not others.
@tamas-pamas4 жыл бұрын
Is there a way to see stored triggers?
@SteveGriffith-Prof3ssorSt3v34 жыл бұрын
If you are using PhpMyAdmin, open a table and you should see a tab at the top called "triggers".
@tamas-pamas4 жыл бұрын
@@SteveGriffith-Prof3ssorSt3v3 Thanks :)
@jaswanthnelam4 жыл бұрын
why are you using so many browsers?
@SteveGriffith-Prof3ssorSt3v34 жыл бұрын
I am a web developer. I have to be able to test what I build on multiple platforms.
@bhatnagarcapital3 жыл бұрын
I am in love with you . I love you Steve Griffith . I would like to be your friend .
@satoutatsuhiro8663 жыл бұрын
would have liked, but it had 777likes and 7 dislikes ^^