Unfortunately, the object I'm updating is a sealed class that I cannot modify. Good answer. When working with large data sets, there is huge performance benefits to only updating rows that will receive a change. 2- Use Join between Inserted table and deleted table. How to improve performance? So if you only change 1 field against the object and then call SaveChanges (), EF will only update that 1 field when you call SaveChanges (). The last example also works well for stored procedures as the temp table can be replaced with parameters e.g. rev2023.5.1.43405. How to force Unity Editor/TestRunner to run at full speed when in background? Why are we joining on DeSChedule when that is the table we are trying to update the record in? Now write the code roughly as follows (you'll have to alter it to match your context name etc): The MapToModel method could be even more complicated and do all kinds of additional checks before assigning the view model fields to the entity object. I'm learning and will appreciate any help. The overhead is approximately the same as maintaining an additional simple index. Is there a generic term for these trajectories? How to make sure change_tracking statistics stays updated, SQL Server Logon Auditing and Reporting the data from a DB Table, Validating SQL Server Change Tracking Synchronization, intra-query parallel thread deadlocks with only Page Locks with snapshot isolation and change tracking, What are the performance implications of using checksums vs change tracking for SQL Server. Browse other questions tagged, Start here for a quick overview of the site, Detailed answers to any questions you might have, Discuss the workings and policies of this site. This causes writes to the physical tables/indexes, recalculating of indexes and transaction log writes. I'm trying to make a website where there is a form that contains input type fields that are editable. The best answers are voted up and rise to the top, Not the answer you're looking for? My first blog. Can you still use Commanders Strike if the only attack available to forego is an attack against an ally? Since you are dealing with large data, it will be quick in making the changes as soon as any input is changed. Thanks for contributing an answer to Database Administrators Stack Exchange! I'm learning and will appreciate any help. ', referring to the nuclear power plant in Ignalina, mean? This also makes you application more scalable. A lighter alternative to Change Data Capture is Change Tracking. This works fine, as long as every column isnt nullable. My instinct would be to write a wrapper and default to using serialization comparisons. ', referring to the nuclear power plant in Ignalina, mean? Firstly, don't make your callers do all that work! Basically, the main difference is that SqlTableDependency send events containing values for the record inserted, changed or deleted, as well as the DML operation (insert/delete/update) executed on the table: SqlDepenency doesn't tell what data was changed on the database table, they only say that something has changed. Using <> or != will get you into trouble when comparing values for differences if there are is potential null in the new or old value to safely update only when changed use the is distinct from operator in Postgres. Ubuntu won't accept my choice of password. Since the source tables are very big, I cannot just select a checksum over all candidate columns or something like that. Which language's style guidelines should be used when writing code that is supposed to be called from another language? So when the trigger fires it updates every row in the target table that matches but I only want to update the one that data has changed. One method is to compare each column in the WHERE clause separating each comparison with an OR Gotcha. How are engines numbered on Starship and Super Heavy? To subscribe to this RSS feed, copy and paste this URL into your RSS reader. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. I don't know, why you want to do this, but here are several possibilities: You need an unique key id in your table, (let's suppose it's value is 1) to do something like: Old question but none of the answers correctly address null values. The overhead due to false triggering is a tiresome, but even in worst-case the expensive query need not be run any more frequently than it is currently. So on a big table, issuing an. Asking for help, clarification, or responding to other answers. "Signpost" puzzle from Tatham's collection. Sending an update to myslq with the same value uses more resources, If there are no changes then send nothing To learn more, see our tips on writing great answers. Here is my way of handling this: In this example, you have a single entity called Person: Now let's say we want to create a view model which will only update Dob, and leave all other fields exactly how they are, here is how I do that. The method shown in that answer doesn't filter out rows that exist yet do not need to be updated. The user has the possibility to change it. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. If the updates you're expecting affect an index (and only if), you could use the system table sys.dm_db_index_usage_stats to detect the last update to an index on the table in question. Identify blue/translucent jelly-like animal on beach. Does a password policy with a restriction of repeated characters increase security? Read more about it here. Of course, there's always more than one way to bake a cake. Making statements based on opinion; back them up with references or personal experience. Note how inside the EXISTS clause the SELECT statements have no FROM clause. Something like this: i.ColA <> d.ColA OR i.ColB <> d.ColB etc. If this is all baked into you data access layer then fine, some ORMs for instance provide such optimisation as an option, but you don't want to be manually writing and maintaining it for every update statement in your application. Stack Exchange network consists of 181 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. Why does the narrative change back and forth between "Isabella" and "Mrs. John Knightley" to refer to Emma's sister? Some may say to use the UPDATE function but this will NOT work for you. Content Discovery initiative April 13 update: Related questions using a Review our technical responses for the 2023 Developer Survey, How to return only the Date from a SQL Server DateTime datatype. Clean up your queries and simplify logic with CROSS APPLY. If you were to compare query plans between the first method and the EXISTS/EXCEPT method, it appears the latter will generate a slightly more complicated execution plan. Not the answer you're looking for? rev2023.5.1.43405. rev2023.5.1.43405. Yet another option is Reflection whereby you can do the same thing dynamically (Edit: see the Single Smart-Update Method in Dan1701's answer). If I comment out the where then the modified information is updated in every case. If your object were passive and had public fields instead of properties, you could write a more elegant Update() procedure, accepting the field as a ref parameter: With the overhead of OOP, however, you have more work to do.