Advanced Dapper in C# - SQL Transactions, Mulitple DataSets, UDTs, and more
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- Опубліковано 22 лип 2024
- Source Code: leadmagnets.app/?Resource=Adv...
Full courses: www.iamtimcorey.com/
Blog Post: www.iamtimcorey.com/blog/2056...
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If you have watched any of my videos that include data access, you are probably familiar with Dapper. Dapper is a micro-ORM built by the team behind Stack Overflow for the purpose of getting data in and out of databases. It is quick, easy to use, and easy to debug. In this video, I am going to cover some of the advanced scenarios that you can use Dapper with including User Defined Table Types, Transactions, multiple data sets and more.
Timestamps contributed by: Ralfs HBK
0:00 - Intro
1:34 - Demo app: Database overview
5:20 - Demo app: Class Library overview
7:17 - Multiple object mapping
15:56 - Multiple object mapping with parameters
19:00 - Multiple Data sets
21:44 - Multiple Data sets with parameters
23:43 - Parameter output form database
28:43 - Safe Transactions
37:25 - Insert Data Set
42:37 - Concluding remarks
Thank you again! Your tutorials are phenomenal. I only learn concepts well when I understand the practical uses and the logic behind the concept. You are clearly a master educator and I can’t thank you enough.
You're very welcome!
thanks tim, you saved me a ton of time looking up all the cool tips from every where .. I find it really easy following your tips and you actually make it look so simple, yet you still show a glimpse of its full potential enough to help everyone watching your videos to pick the best scenario for his needs ! I appreciate your hard work !
You are welcome.
Very informative and worth while. very productive 44min. Watching in 2021 questioning myself why didn't watched it before, could had saved me from lots of grief in some of my projects. Keep up the good work. Thank you!
You are welcome.
Genuinely you have overpowered me with your communication skills and the way you explain each and every point.
Happy to hear that!
Man thank you all this information you gave at each answer. You're taking care of your channel as your house. This is what is called effort! I hope you get millions of subscribers in short time.
I appreciate that.
Thanks Tim, your videos have really helped me professionally :)
Great to hear!
Thank You Tim Corey for your really amazing tutorials, you explain the technical aspects really well and have helped me out of challenging coding situations a number of times now.
You're very welcome!
thank you for all the great contents. I don't comment often, but I have watched many of your videos and liked all of the videos that I have watched.
Thank you for engaging with the community and sharing your thoughts!
Just want to mention you've been so much help as I go through college for this. Right now, I simply don't have enough money to help in return, but once I land my first job, I want to contribute back!
I am glad my content has been so helpful.
Great video Tim, I've been using dapper for a couple of years and appreciated this video.
Thank you!
"A junior developer writes simple code to do simple things. A mid-level developer writes complex code to do complex things. A senior developer writes simple code to do complex things." by Tim Corey
I agree. :-)
Brilliant!
Thank you Tim for this tutorial. I really liked the insert set way with UDT types, I already used it in my project!
Awesome!
As always, Tim Corey gave a top level instruction on using Dapper.
I am glad it was helpful.
Thank you Tim for this simple and clear explanation. I was lucky enough to see this video today and you added the link to the source code just one hour ago. Means I was watching the video while you added it :)
You're very welcome! I work hard to keep everything current
As a software engineer, when I was a student I didn't get many topics in database, and I thought that it is impossible to learn how to do it. Thanks to you I am more confident in doing database connections now. I really appreciate it. Thank you.
Glad it was helpful!
This Video saved me a lot of time, I wanted to chose between EF and a better alternative for a project. Thank you Tim Corey.
You are welcome.
Excellent video Tim. This was very much needed. In fact, helped me a lot with some issues that I was having recently.
Awesome!
@@IAmTimCorey Happy Thanksgiving
Excellent video Tim!! I'm new to your channel.
Thanks for everything you do for the community. It's awesome!!
The bit about having to read the results of the QueryMultiple call in a particular order brought me to a screeching halt. That's tight coupling at its finest. If anyone ever inserts a select between the two existing selects, our system will have a bad day - at least in dev and pre-prod that is. 😀
Thanks again!
-Mark
I'm not sure I'd call it tight coupling. Order is almost always important. That's why we have FIFO objects.
Thanks Tim for the video and tutorial on Dapper.
You bet!
You are a teacher of teachers!!!! MAN YOU KNOW HOW TO TEACH!!
Thank you. I strive to educate rather then just dump knowledge. I really appreciate your comment!.
It's a so useful video which truly make learning C# much easier for me!
Glad to hear that!
I have just 2 years of experience working on WPF technology, I have learned so much from you. Thank you very much from my heart ♥. ☺
Still waiting for WCF tutorial
You are welcome. I’m still trying to fit WCF in.
Thanks Tim, Your way of explanation is crystal clear. Got a very good idea about dapper, thinking to implement in my new project.
Glad it was helpful!
@@IAmTimCorey Hi Tim, I have general query. Is it really make a differences (In term of performances) to write async task methods in repository/controller classes. Please let me know your point of view.
Videos on Dapper OR/M were great.Thank you for those.
You are welcome.
It's soooo cool! Thanks for this tutorial Tim! Is totally worth his weight in gold!
Thanks!
Amazing examples as usual, Mr. Corey! I really need to wrap my head around this DataSets to understand how to insert the whole prepared table onto another empty table. But this is fine.
Microsoft is working to make this easier, but it probably won't happen until .NET 9.
The evolution of Microsoft Applications Blocks.. Excellent video Tim, greetings from Chile
Thank you!
Now I understand 'Dapper' . thank you sir.
Great!
Excellent video
thank you for what you do for us always shine in your videos and continue in this way you help us a lot and make things easier for us and short the time to learn
You are most welcome. Thanks for watching.
0:00 - Intro
1:34 - Demo app: Database overview
5:20 - Demo app: Class Library overview
7:17 - Multiple object mapping
15:56 - Multiple object mapping with parameters
19:00 - Multiple Data sets
21:44 - Multiple Data sets with parameters
23:43 - Parameter output form database
28:43 - Safe Transactions
37:25 - Insert Data Set
42:37 - Concluding remarks
Thank you. Much appreciated by MANY.
@@IAmTimCorey As are your tutorials!
Super clear and easy to follow along!
Thank you!
Thanks for this Tim! Great help
You are welcome.
Thanks Tim,
Nice video, I learned really this in details
Thanks for watching
Great video! thanks Tim
Very welcome
Great vidéo! You've converted me to Dapper, I love this tool!
Awesome!
Nice video , and that new sketch is awesome
Thanks! I'm glad you like it.
Thanks a lot, I have coped with my problem really fast! Thank you!
You are welcome.
very clear, thanks a lot. Going to enjoy it.
You are welcome.
Thanks a lot, especially for "Insert data set" section!
Thanks Рамис for watching
Thanks for this course
You are welcome.
Excellent demo which i've already used (addicted to dapper)
Thank you!
Great video as always. Thank you ! 👍
You are welcome.
This videos are gold
Thanks!
Really nice. Thanks for sharing that!
You are most welcome. Thanks for watching.
Hello Tim, I want to ask if someone has a generic internal class SqlDataAccess like you used it in your some projects. Is it possible to do multi mapping with generic classes, right? Dapper needs to know where the child object is in the generic parent, am I right? Or how to do this? In our projects we always have at least one 1 - n tables. Thank you.
Thank you. This was very helpful.
You are welcome.
Thank you. Very good tutorial!
You are welcome!
as always...!! REALLY nice and clear
Thank you!
Fantastic video Tim! I'm really enjoying Dapper so far. Thanks for introducing me to it.
My pleasure!
Great video! Thanks a lot !
You are most welcome. Thanks for watching.
I have been looking for a way to capture errors using Dapper. I can get the parameters back from a stored proc but what happens if there is a SQL error? I have been looking for different methods but it seems Dapper, when encountering an error, just fails silently. For example, if I am missing a parameter for a stored procedure I just get nothing back. No throw of any error.
Any recommendations? I found some information on connection.InfoMessage but that is not available (anymore?)
Hi, Tim you are great man, thank you for video. All of just and a understand how to work this is a Dapper that it.
Thank you!
Thank you for another great video Tim, I'm a long term fan of your videos and instruction, you have helped me an awful lot. I spent a year learning and using EF (love the code first approach) but became very (very!!!) frustrated when it went wrong. I've always manually created Databases and am very comfortable with SQL/SSMS/SSDT so using Dapper feels like taking back some control for me (especially alongside SSDT).
I am really struggling however with Dapper "breaking" when trying to use simple non-mapped properties, such as FullName => $"{FirstName} {LastName}" and having to strip out relational properties e.g List in order to use Dapper. It seems to be a lot of extra work to create subsets of classes/DTOs, just to be able to use Dapper. I appreciate it's a micro ORM, and I want to use it, but it feels too limited in practice. Would you recommend alternative ORMs that cope better? I am looking around, but as always appreciate your recommendations, which I know come from many years of experience - so thank you for any pointers.
You can write a custom type map (inherit from DefaultTypeMap) and create an attribute to ignore properties.
Hi Tim,
At 37:53, you mentioned data table is not much used anymore, with dapper doing mapping for us, could you please guide how to use object mapping for bulk insert data ?
Thank you
Great Video! Do you have a dapper video explaining how to map property names to column names if they aren't exactly the same? I.e. column first_name to property FirstName?
EDIT: I'm trying to follow the naming standards for PostgresQL
Hi Tim,
How can we execute the dapper query if the Person have more than one phone number. e.g. A person object has List
Well done, Tim. I really like your tutorial video's. I learned SQL and C# all by myself by watching this kind of tutorials. But what I am missing is UPDATING a single record in a database using dapper, C# and models. Most tutorials are handling select and insert, which according to me are not the most difficult commands. Thank so far for the wonderful video's.
I do that in the C# Application from Start to Finish course. Basically, update is just like insert, only it is an update command.
@@IAmTimCorey Thanks Tim. Yes, it shouldn't be that difficult. My application doesn't update because it doesn't find the ID. Back to debugging. Keep up the good work.
Hi Tim, In data access videos prior to this one you've used generic methods like : public static List LoadData(string Sql) and passed in the relevant object and SQL statement. Is there a way to do something similar using Multi mapping by providing the object list and params?
That gets more complicated and not necessarily as useful, but it is possible.
Great video Tim
I am currently using dapper in one of my projects.
I would like to know if it’s possible to use SqlDependency to get the dbchanges ?
I need to use signalr notifications when a record changes in db.
Kindly let me know if it’s possible
Thank you
Hi Tim, is it possible to have a generic Query Multi-Mapping method? Just like you craete the generic methods in the TimCORetail project.
Hi Tim, thanks for your videos about c#, wpf, sql,, ect. I learn a lot of things. For this Dapper video i have a question. If is posible to update multiple rows with dataset like the InsertDataSet example? Thanks for your answer.
Yep. That's just a change in how your SQL is written. No changes needed on the Dapper side. Just change what you do with the data once it gets to SQL.
Excellent, that's what I need. thanks
Excellent!
Just one question when you pull data from multiple table, does dapper do it parallel or in sequence, if it does parallel then its lots of fun.
top notch as always :)
Thank you!
Hi Tim, how do you perform a json HTTP patch operation using dapper where you got dynamic columns to update, I mean how do you build the query / stored procedure without it being vulnerable to SQL injection
Thanks TIm. I've just come across "Unit of Work" concepts, although nothing related to minimal APIs, which I'm using. Even so, I can't see any point in UoW when Dapper has this transactional capability. Am I missing something?
Hi Tim, thank you for another great video. I have been struggling with obtaining a return value when doing an execute with dapper. For instance when a new customer is added i would like the output from my stored procedure for the ID column. is there a workaround with dapper to make this work?
That's what I did here: ua-cam.com/video/eKkh5Xm0OlU/v-deo.html
Hi Tim, how about when you get null for that parameters or the user can decide to pass the parameters or not? thanks a lot
For an SQL with inner join wouldn't just be easier to return a datable from a reader using dapper? Less messy? Or is there a generic cleaner way to do this?
Is it a best practice to use dirty reading inside SQL statements? Thank you in advance!
Hi, is there any way to add objects with foreign keys using dapper? Like we have Author and Book tables. The book table has Author ID as the foreign key and author has a list of book objects. And when I add an author object to database I would like to add whole object also with the list of books in one query.
You can either make multiple calls or you can pass all of the data to a stored procedure and have it do the multiple inserts. That's a limitation of SQL, not Dapper. EF does it by making multiple calls (actually one big call with multiple statements, I believe).
Thanks Tim!
You are most welcome. Thanks for watching.
Thanks Tim, this was really nice. just wanted to know if the above strategy of invoking procedure and sending parameter is same for calling oracle procedure except for putting colon(:) instead of @ before the parameter
I believe it is but I don't believe I have called Oracle using Dapper yet (I avoid Oracle if I can).
Hi Tim, Love your stuff. One quick question. I am working with dapper and SQLite. I have gone through this Advance Dapper video and its great. My question is you call out a Demo 1, Basic Dapper lesson but i can't find that one. I would like to go through that one as well to get the complete picture. Where can I find the video related to Demo1_BasicDapper?
Here is my intro to Dapper lesson: ua-cam.com/video/Et2khGnrIqc/v-deo.html
Hi Tim, thanks for the great video as always! Just one quick question. For the MapMultipleObjects example, How would we go about using this in practice, for example populating a list with the returned people rather than outputting to console? As well, is there a way for us to make it a more generic function so only the SQL code along with classes would have to be passed to the function rather than rewriting for each case? Thanks!
We outputted it to a console but you could just return those objects directly. I don't believe anything would need to change. As for making it generic, it can be a bit trickier but you can make this generic (if you limit it to a set number of mappings).
Great vid.! Thank you 🙂
You are welcome.
Hi Tim, thanks a lot for this video, i have a question, how can use Query if i had a query with inner join to 3 or more tables with different id for relation?, in my class i have a Class Property for each one
Not sure what you mean. Dapper just cares about the output. The output will be rows and columns. For each column, you need a property. Dapper will then create an object per row. It doesn't care how many joins happen in the query.
loved the video as I do all of yours but one question, if you have a person table with physicaladdress(INT) and mailingaddress(INT) and an addresses table with addressid(INT) ... how can you do sql statement to get join these tables to give me a result set that has each person in the person table and their respective mailing and physical address?
That would just be an inner join statement for each address type (select p.*, phyAdd.*, mailAddr.* from person p inner join address phyAdd on p.physicaladdress = phyAdd.Id inner join address mailAddr on p.mailingaddress = mailAdd.Id).
Thank you, Tim! I have two questions.
How should be MapMultipleObjects() method if I have many entities (let's say15 for example) and I want to make a data mapping in this long class hierarchy?
In some cases a class property is a List and any object of that List could have a property that's another List. Which is the best way to handle this mapping with Dapper?
Thanks in advance!
It sounds like you would be better off doing multiple SQL calls instead. That would keep it clean and simpler. Still, that is going to be messy. If you have a choice, you might want to look into a NoSQL solution like MongoDB. That would reduce your calls to one.
I have a doubt: Does Dapper handle connection close method in case of an error condition or do need to implement try catch and finally when we call the Query or Execute method of SqlConnection class.
That's outside of Dapper itself. Dapper just handles the extension methods that do Query and Execute. The actual connection is given to Dapper. That's a SqlDatabase connection (from C# itself). That's why we instantiate the connection in a using statement. That using statement will ensure that the connection gets closed even if there is an exception.
Is there any good reason to create a IDBConnection (the cnn variable) instead of just a SqlConnection? Saw you do it in the Web Api Course on your website too.
It is an interface, which allows us more flexibility to change the implementation later on without causing issues. Also, we can reuse that code other places and just change the implementation to match the database type we are using.
Hello Tim great video. I was wondering could we not do most of the things with stored procedures. Would this be better or worse or is it a matter of preference because I lot of people are not nececarrily very proficient with sql. For example the transaction if I recall correctly could happen from the sql side throught a procedurs(if I am wrong it is because I am only using sql for basic stuff).Or for example the sql querried from the c sharp side could be used as a stored procedure.
Whenever possible, I recommend doing it on the SQL side. However, there are times when you need to do transactions on the C# side. I do so in the TimCo Retail Manager, because we need to save the header for a sale and then each detail record. There isn't a good way to transmit all of that data to SQL at once and do the transaction in SQL. So we do the transaction in C#.
thata our bro and our teacher too well done sir
You are welcome.
Hello Tim, thank you so much for this video. Do you have a video which shows how to set up pagination with Dapper using MS SQL's FETCH/OFFSET features for pagination? Or if not if you could guide me to a reference to study? Thanks so much.
I don't have an example to show you but I can add it to the suggestion list.
Nice video, thank you.
You are welcome.
Hi Tim, thanks for this amazing advanced query examples, help if you could share us possible to parse the XML columns into respective classes using Dapper?
I don't believe so.
Thanks Tim, I have a question about the first method, in person table you have CellPhoneId column which you use it in sql statement, how do you insert CellPhoneId to person table ? cause there is no such a field in models but in person table.
On an insert, you would need to pass in the CellPhoneId. So, you would probably need to add it to the model.
Hi Tim, is it possible to have a generic Query Multi-Mapping method?
What if after a join there are 2 ID columns? How does it know which one goes to hwich model? If I alias them will it figure it out? But what if for both models the property is named just ID?
Think of the result set in the query window. That should make this easier to visualize. You wouldn't want to have two columns named the same thing (ID) since you don't know what each communicates. Therefore, you would alias one (or both). Dapper just looks at the result set and maps that, so if you have two IDs in your model, only one can be called ID. The other will probably be called AddressId (for example). If you aliased the column in the result set as AddressId then it will properly map to your C# model.
Thank you for another lesson! Is it possible to make a video that includes integration with docker and jenkings?
Docker is coming. I don't have a video for Jenkins planned but I do have a course that makes use of Azure DevOps (an alternative to Jenkins that, in my mind, is far superior to Jenkins). The course is called Application Lifecycle Design: www.iamtimcorey.com/p/application-lifecycle-design
I mentioned this in your Entity Framework video - you should definitely check out FOR JSON PATH. Especially since you like stored procedures so much. Your MapMultipleObjects method would be one stored procedure call that returns a string and then you deserialize that string into your FullPersonModel object. Quite simple. And the brilliance of it is that all the "nesting" happens on the database instead of your C# code.
Thanks for the suggestion.
@@IAmTimCorey No prob. I've learned a lot from you over the past few days, I really appreciate what you're doing. I haven't researched FOR JSON PATH a lot, but I know that I haven't run into any performance issues with it. It works identical to using the old FOR XML if you've ever used that. I think it would make for a nice video in your collection - whether that be a positive or negative review. As always, thanks Tim!
@@IAmTimCorey Just a couple of pointers if you decide to play with this.
1. Make sure you declare an nvarchar(max) variable and then select your query into that variable. Then return the variable. If you just run the query, the stored procedure will cut off the string that it returns at like 400 characters maybe, I don't remember the number.
2. This is where this gets controversial to me - you can do this same thing inside a function and return the json string from the function. Then use the function inside of a select query. Point of this is to methodize/consolidate your code, and you can nest these functions are far as you want. But Functions inside of subselects are a no-no. Like this:
create function GetAddresses
(
@UserId int
)
returns nvarchar(max)
as
begin
declare @result nvarchar(max)
set @result = (
select *
from Addresses
where UserId = @UserId
for json path
)
return @result;
end
create procedure GetPeople
as
begin
declare @result nvarchar(max)
set @result = (
select *
,json_query(dbo.GetAddresses(u.Id)) as Addresses
from Users u
for json path
)
return @result;
end
Another great vid Tim. Have you done any about SQL Database Migration techniques used alongside Dapper?
Here you go: ua-cam.com/video/ijDcHGxyqE4/v-deo.html
We use this system in the TimCo Retail Manager series.
@@IAmTimCorey Still replying to comments on years old videos, nice! Thanks!
in the given example table value parameter we used "BasicDT" needs to be present in the sql server database ?
Yes it does.
hi Tim. great video. .is there any video which explains the "Demo1_BasicDapper" folder on your project? I followed your "easiest way to connect to SQL with c#" video and thought this is the continuation. Please comment.. Thanks in advance
:)
Hi Tim, Can you please show an example for "Update list of Objects with Oracle Database" using Dapper.
I will add it to the list. Thanks for the suggestion.
I would love to see a video from you covering Dapper implementations of repository-, unitofwork- and specification patterns with possible eager loading of navigation properties. Everything I find on this revolves around Entity Framework, but I think you have made good arguments against EF and I prefer avoiding using it for anything else than authentication and user management. I am really hoping that Dapper can be a good alternative. Maybe some extensions that have been made to Dapper and available as nuget packages can make it even a better choice.
I will add it to the list. Thanks for the suggestion.
@@IAmTimCorey +1 for this idea. From browsing the net, I get the impression that the repository pattern allows you to use any data persistence mechanism you'd like...as long as it's Entity Framework :)
+2 for this idea, EF and I prefer avoiding too.
Strategic question: Dapper vs EF, knowing that for 'small- to mid-sized developers (like me), once you one as your tool, you are most likely to re-use that tool over and over again for most (all) of your remaining projects. I write (mostly, currently) Windows desktop apps, but can foresee doing iOS /iPad and web apps. I used to use ADO Record Sets in VB6 and was quite comfortable with it. Even wrote methods that would cycle through all the Controls on a Form and build a RS of fields that needed to be updated, so that such would never have to be manually enumerated, which made coding much faster and less error prone. And used the msBind so that the Controls always matched the underlying recordset record automatically. Loved it. As I move forward, what would be the pros and cons of "Choose Dapper, and never look back at EF" ?
There's a lot to that situation. I've got a blog post on it but it is outdated and needs to be updated to reflect EF Core. The basics, though, are that EF can be easy until it isn't. It can be easy to get data in and out of your application until you find a performance issue (common with EF) or until something breaks in EF (not as common but when it happens it can get messy). EF writes a lot of code for you. Generated code can be great but you are still responsible for it. If it breaks, you are the one to fix it. With Dapper, there is no generated code. Most of the work is done in the tooling and, if it breaks, it is something that the Dapper team fixes. Your code is simple. However, you are responsible for knowing how to get data in and out of your database. I would argue that you should anyway, since you are supporting EF doing exactly that (and by supporting, I mean you are responsible for knowing how it works, not just saying "the magic does stuff"). Dapper is incredibly fast (almost as fast as raw ADO and a lot more flexible). EF6 is slow, and while EF Core can be a lot faster, it does depend on the queries it writes. You are responsible for checking those queries to make sure they are efficient and, if not, for replacing them with efficient ones (if you care about efficiency).
Hi Tim, just started purchasing your courses and enjoying them.
What is your opinion on Telerik for win forms and mvc?
Would you consider doing a tutorial?
Thanks again for the great exercises!
I like Telerik. They've got some great products and I've used quite a few in the past. As for doing a video on them, I doubt it unless they sponsor one. The reason why is that I don't often create videos where a person has to make a purchase in order to have the video apply to them. I'm even careful about avoiding showing off the Enterprise features of Visual Studio too much since that too is a paid product.
Hi Tim, Great video! However what is the difference between using dynamicparameters and List to insert using dapper?
Dynamic Parameters is an object type from Dapper that allows us to specify more specific information about each parameter (is it an output parameter, what is the type, etc.) The List allows us to send data for more than one row of data. So we can call the Insert query once but insert five rows, for example.
Hi, Tim. I've been having trouble when using Dapper. It won't show up in my Intellisense and returns error that The type 'IDbConnection' is defined in an assembly that is not referenced. You must add a reference to assembly 'netstandard, Version=2.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51'.
It sounds like you created a .NET Standard class library instead of a .NET Framework class library. You might also be mixing library types. Try creating a .NET Framework class library instead. See if that solves the issue.