Entity framework delete record if exists
Entity framework delete record if exists. In this tutorial, you: Mar 22, 2012 · to delete the entities. Check Username Availability (Exists) in Database using jQuery AJAX in ASP. Reference(c => c. Jan 31, 2017 · Entity Framework Core does NOT have . StackOverflow Related Questions. Probably cos they are for older versions. Then you set your navigation property to a newly created property this breaks the old relationship and creates a new one. edited Feb 13, 2021 at 7:32. tbl. Since the entity you created is not in the database it will be added. ExecuteStoreCommand(deleteOld, oldestAllowedTime); Feb 17, 2011 · Is there any way I can tell EF to not worry about the number of rows a DELETE or UPDATE do or don't do? I'm trying to delete a row from the database, but because the row doesn't exist, EF throws an exception: DbUpdateConcurrencyException. Not 100% sure how to turn it on/off in Entity Framework but basically what it's telling you is that between when you grabbed the data out of the database and when you saved your changes someone else has changed the data (Which meant when you went to save it 0 rows actually got updated). Tests Feb 8, 2017 · 4. The entry provides access to change tracking information and operations for the entity. ) Mar 16, 2020 · I want to seed some data using EntityFramework in . entity-framework. Based on the current list of migrations in your code it will apply the missing migrations. Apr 12, 2014 · The Code. Id == ID)); If you are more concerned about fetching the entry data, use one of the check if exists, delete by ID ways. Mar 21, 2013 · I'm using Entity Framework 5 and I'm trying to delete an entity that doesn't have a primary key. 4. For example: context. Although, in your case it looks like you just need to extract new objects, you can use var newCountries = data. However, when I try to delete a catergory, and if there's a product with that catergory I shouldn't be allowed to do so. You can also use the query that contains a filter as shown in the following example. Other queries that use the same context will not see the deleted User because the context has the entity marked as deleted. Feb 21, 2023 · When ExecuteDelete is called, a DELETE statement is generated and executed by the database. Get the code. Code == E. By this I mean my table doesn't even have a primary key. Any(u => expr); Jan 18, 2012 · Entities are deleted by their key. Solving database concurrency issues related Dec 27, 2011 · Note: this will throw an exception of you're trying to delete an object which does not exist. Remove() to delete each row as shown below: C#. DeleteFromQueryAsync(); DeleteFromQuery gives you access to directly execute a DELETE statement in the database and provide a HUGE performance improvement without select and load objects. What I want my code to do is, to do is to prevent me from deleting a Catergory May 17, 2022 · Entity Framework Add if not exist without update. Remove(entity); Using this extension method, the removal can be made The DbContext. " I believe this is because EF is somehow detecting and keeping the first data pull, but I am just un sure on how to correct it. First of all you need to create instance from your Database entities,after that you should select your desired object,then delete it : where rows. Name)). Col2 = b. This is right -> no rows were deleted. Department = null; How do entity framework handle concurrency access,when issuing multiple delete & create opeartions 4 Purpose of checking if the entity state is deleted before deleting Apr 15, 2014 · I have some Parent records already inserted in the database. Sql("DELETE FROM [table]", true); Oct 12, 2012 · First find the entity which you want to delete using Find in EF and pass the entity to below function. How do I delete a record by its primary key without first doing a SELECT statement to load the entity? Mar 3, 2013 · 0. public int StudentId { get; set; } That's a side-effect of a feature called optimistic concurrency. 1 and I'm facing an issue: I've got two SQL tables (so two DbSet<>): public virtual DbSet<TableA> TableA { get; set; } public virtual DbSet<TableB> TableB { get; set; } Nov 7, 2016 · 2. UserName is not a primary key property, you need to find entity. B. RemoveRange(db. There is an extension for EF on github that allows you to update and delete entities with a single call to the database. If the function returns true it means cannot be deleted and foreign data exists. You can add, modify, and remove data using your context and entity classes. I could run a re-query, but I don't want to do that. Sep 29, 2022 · Right-click the Controllers folder in Solution Explorer, select Add, and then click New Scaffolded Item. And you could do something as simple as IF RS. Feb 12, 2022 · Learn how to delete records from the database using Entity Framework Core. Deleted; // cascade delete. Where(thePredicate)) theDbSet. Retrive(c => c. e. Jul 23, 2016 · The Picture record is replaced (delete + create of a record) whenever the parent is updated with a new picture; The picture is optional; Always keep control over whether the picture is loaded or not; I'm using fluent API to define the relationship. Users. Col1 = b. You aren't really talking about concurrency here, as your question title suggests. Remove method results in the entity's EntityState being set to Deleted. NET 6 and I would like to essentially upsert an entity to a table - a fairly simple ask. FirstOrDefault(); db. Contains("John")). I'd add that you can get really concise with pattern matching, with the added benefit of scoping your variable so it can only be used if it's not null. The Remove () method of the DbContext is used for deleting records from the database. Where(c => c. I am developing a MVC application using EF Core. Entry(deleteMe). See full list on tektutorialshub. DeleteObject(ts); db. When I delete a Catergory it also deletes the associated product. Code); Nov 1, 2017 · 7. RemoveRange, so I have no idea how to perform this operation. That's only appropriate if you're sure the object exists. You create a new in-memory entity with an identifier you assume is in the database. Name. Optimistic concurrency patterns using Entity Framework. So you can check if it is > 0 or not. Where (x => !context. Select Server Explorer( it is oftentimes on the left) 3. SaveChanges. UpdateGraph(entity); Insert entity if it doesn't exist, otherwise update AND insert child object if it doesn't exist, otherwise update. This usually happens when you have a migration that creates a table and the required table is already present in your database so, when you update the database from classes in Migration, it will try to create a table and will fail because the Create command will not be executed as it already has that specific table. Jun 17, 2014 · I am working on EF database first application and I have encounter the situation where delete records from a table which has no primary key. SaveChanges(); Apr 26, 2021 · Intersting problem! Using SDKs it won't be possible to delete the document. Mar 28, 2023 · Entity Framework Delete by ID is used to delete the record based on the ID; we can make use of the Remove or RemoveRange method to spot it as Delete. EOF THEN (attempt the delete only then) END IF. There are definitely at least a couple simple ways to delete multiple records in EF Core. ID == 1. You change the EntityEntry<Person> to have a State of Deleted. 0, if an entity is using generated key values and some key value is set, then the entity will be tracked in the Modified state. var db = new DatabaseContext2(); //delete table - this doesnt work. Currently I came up with the following code but it still keeps making new records even if the row already exists. static void Main(string[] args) {. Cliente == cli); This is inside a foreach loop. public bool CheckIfEntityExistsByEntityId<T>(Expression<Func<T,bool>> expr) {. In the disconnected scenario, we can attach it to the context and mark it as Delete state. If records with the passed ID exists, those records need to be deleted, and then inserted again. Save(); call them in that order. I have the following code: var countries = GetCountries(); using (var scope = scopeFactory. Net MVC Oct 7, 2022 · Others already have pointed out FirstOrDefault will return null if no item matches. Nov 21, 2018 · In EF Core, if you don't care if the object exists or not, and you just care that it will not be in the DB, the simplest would be: context. An easy way to apply this is to wrap the select statement of your view in another select. Here you will learn the overview of working with the DbContext to create a database and interact with it using EF Core 7 on . The ObjectStateManager cannot track multiple objects with the same key. The following are Student and Grade classes. delete complete database, let entity framework rebuild Apr 1, 2014 · DELETE FROM Table1 WHERE (**Col1**, Col2) IN (SELECT Col1, Col2 FROM Table1 a JOIN Table2 b ON a. Any. A couple options: May 23, 2022 · I'm using EF Core and . Any () is the the best way to go if you just need to check the existence. Single(); context. This means that a row for the entity is assumed to exist and it will be updated when SaveChanges is called. The connection to the database is created using the given database name or connection string in the same way as is described in the documentation for the DbContext class. Id == Guid. To delete an item: I know how to delete items I asked what is: "mark all these items as deleted". Ideally I would write plain sql query like this: select id from dbo. Where(x => x. If the key value isn't set, or if the entity type isn't using generated I want to know if a record exists in a database to avoid duplicate data. According to the EF6 docs: If you have an entity that you know already exists in the database but to which changes may have been made then you can tell the context to attach the entity and set its state to Modified. ExecuteDelete (); The above code will generate the following SQL statement. Prices) db. You just want to ensure that a record's natural key is unique. Jan 13, 2022 · Delete a Single Entity with EF Core. SaveChanges(); Update : If your result set is a list, I mean more than one record you can use this solution : db. Open your project in Visual Studio using the ". DeserializeObject<List<Customers I believe the aim is to delete the database itself and recreate it using EF Code First approach. Students. select d). Remove(item); } Db. Apr 18, 2020 · In other words, I want to check if the record really got deleted from the database. The relationships can have DeleteBehavior specified, telling if the related data should be deleted once the master record is deleted. Jul 3, 2015 · Say I have a User that I want to delete, but the User might be referenced by other tables in the database. WriteLine(e); // will happen if record no longer exists } }); Let’s break down the above code and see how you can convert two database calls into one. Note that if the entity exists in the context in the Added state, then this method will cause it to be detached from the context. With this extension you can do something like this: context. All you need to know is the identity of document to be Feb 9, 2014 · I have seen many similar questions but I cant get any to work. OptionVisibleBusinessId == optionVisibleBusinessId); – anhtv13. Jul 29, 2010 · Entity framework exists clause with lambda. await _dbContext. The magic happens when calling SaveChanges() and depends on the current EntityState. Nodes. For example: Feb 27, 2023 · SaveChanges requires one database round-trip for every entity to delete. NET 7 console project along with entities and a context (SchoolDbContext) class. In this case, the Entity Framework generate and execute separate Oct 11, 2017 · Below is my class : public partial class Ads { public int Id { get; set; } public int RegionId { get; set; } public string Name { get; set; } public int Group { get; set; } } Oct 14, 2020 · To delete the relationship, set the navigation property to null. context. Jul 17, 2015 · If you don't mind fetching the entities from database just to delete them, you could do. EF Core API builds and executes the DELETE statement in the database for the entities whose EntityState is Deleted. So simply, you can have below scenerio: INSERT. public Task<bool> CreateEntity(Entity entity){. C#. Modified, it will be updated in the database. In Entity Framework, the DbContext. . That might be what you wish, but not likely. theDbSet, Expression<Func<T, bool>> thePredicate) where T : class. You also did not delete the old entity so it was not deleted from the database. I have two tables with a 1:1 relation. A = A; Call SaveChanges. My question is there an easy way to implement Add or Update using this list. I am using . sln" extention. For reference you can check below article. EF uses the keyColumn and keyValue to determine what to delete, i. The best way is to inspect the Country. 2. EDIT Just realised that I have misread your question. SaveChanges(); // commits the removal. Where(a => a. Usage: bool exist = _db. EntityState property and take actions from there regarding on value (Detached, Modified, Added, etc. Name == x. Aug 6, 2020 · New behavior. The first is get the entity to delete the second to actually perform the delete. Cascade Delete automatically deletes dependent records (child records) or sets null to Foreign Key columns when the parent record is deleted in the database. var deleteOld = "DELETE FROM CpuMeasurements WHERE curr. var dbContext = scope. db. State = EntityState. Jun 13, 2023 · Update List of Records with Entity Framework. Id == 1); A single call should eliminate your DbUpdateConcurrencyException. In the code I wrote it allows deletion. Department). Note 2: this assumes you've set up your entities so that the generated delete command references no other fields than the ID (meaning no Timestamp properties, or anything similar that would be Jan 16, 2021 · For delete, there is no cross-partition deletes and you have to pass in the partition key. I created them using the model first approach of entity framework. Dec 2, 2020 · The data from the API is deserialized from JSON and stored in the data variable as a List<Customers>. Here is my code: var newCliente = new Entities. Jul 8, 2019 · Two entities with one to many relationship such that a voucher has many voucher details, the problem is when removing one item from the collection of the related data (voucher details) and then saving the changes the entity is not removed from the related table. This is because an Added entity is assumed not to exist in the database such that trying to delete it does not make sense. Jul 18, 2013 · 1. You should use ExecuteStoreCommand to execute SQL directly against the data source in situations like this. public void Delete(Entity E) {. NET 7 platform. Assuming that node. If the entity is already tracked in the Added state then the context will stop tracking the entity (rather than marking it as Deleted) since the entity was previously added to the context and does not exist in the database. Oct 10, 2013 · The entity will be in the Unchanged state after calling this method, unless the entity does not exist in the database, in which case the entity will be Detached. Any (x => x. var existingEntity = _context. Remove; call DbContext. Now i want to add some child records. ServiceProvider. One catergory will have many products. EF Core made it easy to delete an entity from a context which in turn will delete a record in the database using the following methods. Entry(item). Mar 23, 2018 · doesn't look like the DeleteData operations are designed to allow for a delete everything in the table operation. Sep 26, 2010 · To delete these records through EF you need to write a routine that starts at the top and loads all the sub items. select o; foreach (var row in rows) { dataDb. I would recommend using something like this: migrationBuilder. string apiResponse = await response. Mar 2, 2023 · To avoid the built in message, you would run a a SELECT statement to seek the data BEFORE you try to delete it. This could be retrieving entity from set or attaching it to the set; call DbSet<T>. DbSet(). And, EF Core does have a RemoveRange() method - it's a method on DbSet<TEntity>, see here in the API docs (as stated in the comment above). SaveChanges method automatically call DetectChanges method to discover any changes to entity instances before saving to the underlying database. By default EF will use all non-nullable, non-binary columns as a key. Remarks. Oct 25, 2018 · But if you haven't done that initially and have already created your tables and relationships, you have to make sure it's applied in the database as well (because for cascade delete EF relies in general to be implemented by the database), by generating new migration and updating the database. Customer where RecActive = 1 and Code Mar 18, 2013 · Your solution is deleting the record with the largest EmployeeId. Then mark all these items as deleted, then call save changes. public static bool Delete ( string nameOrConnectionString); C#. – Ryan Battistone Cascade Delete in Entity Framework Code First Approach. However, Entity Framework seems to be unable to track the fact that the child records should be deleted before the parent. SaveChanges() method is called. As in, if the recordset fails (nothing found) do this, ELSE record WAS found so do this sort of logic . AddRange (missingRecords); Nov 19, 2014 · Handling concurrency in Entity Framework. CreateScope()) {. If no referential constraints in the database are violated the entity will be deleted, otherwise an exception is Sep 26, 2022 · Entity Framework Core API executes the DELETE statement in the database for the entities whose EntityState is set as Deleted. Nov 3, 2020 · 9. In the connected scenario, an instance of DbContext keeps track of all the entities and so, it automatically sets an appropriate Jan 3, 2024 · If no record it would throw an exception instead of null value. Finally, calling Reload on an Added entity that does not exist in the database is a no-op. 9. Jun 17, 2013 · The __MigrationHistory table contains all the information for Entity Framework to determine which migrations are done. Next steps. To force entity framework not to use a column as a primary key, use NULLIF. Hello everyone and thanks for the help in advance. The following is our . DefaultIfEmpty, like SingleOrDefault, is supported in EF 4 but not EF 1. If you are working with Entity Framework that is based on . What is the best way to check if an object exists in the database from a performance point of view? I'm using Entity Framework 1. By mistake I've added one column in my database Named as doj now if I want to drop that column from table using code first approach what should I do. If something happens with SaveChangesAsync() it will return the number of effected rows and this means if value > 0 then true. NET 4. Mar 5, 2013 · How can I quickly remove all rows in the table using Entity Framework? I am currently using: var rows = from o in dataDb. In EntityFramework, SaveChangesAsync() returns an int . Load(); course. linq. Delete(t => t. For scenarios where you need more control -- for example, if you want to include operations done outside of Entity Framework in a transaction -- see Transactions. NET MVC 5 and Entity Framework 6. If this set of columns don't identify records uniquely you will have more problems with using the Session entity (for example delete operation will delete Jan 25, 2018 · Then use DeleteFromQuery () or DeleteFromQueryAsync () method after your query. In the Add Scaffold dialog box, select MVC 5 Controller with views, using Entity Framework, and then choose Add. net core 3. How do you check if Record exists. If you have deleted this table without the database part you have a few options. We can delete records either in connected or disconnected Scenarios. Where(w => w. – Jul 18, 2013 · To be precise it is like so: ObjectContext. Once we update the FirstName and StandardId properties then we call the SaveChanges method to save updated data into the database. Are there any alternatives? c# sql. To do this I followed following steps: Retrieve the Parent(A) records; Create a new child(B) record; Add parent record to the Navigation property of Child. 0 (ASP. Note, however, that an Added entity may not yet have had its permanent key value created. The delete procedure looks like: var voucher = await _voucherRepository Delete (String) Deletes the database on the database server if it exists, otherwise does nothing. Sample Code. Clientes { Cliente = cli, PuntoReorden = 0 }; cliente = rClientes. where keyColumn = keyValue. Content. SaveChanges method saves all changes made in the context of the database. Any (z => z. Entry(course). 2, ASP. Database. Db. Since ApplicationUser. var student = _context. Jan 29, 2018 · I need to check if customer by code already exists in the database using entity framework. Once properly set at the document level, the document will be automatically deleted once the TTL expires. We had the same problem and this is the solution: To force entity framework to use a column as a primary key, use ISNULL. In the Add Controller dialog box, make the following selections, and then choose Add: Model class: Student (ContosoUniversity Jan 15, 2010 · Warning: the 'check if the stored procedure exists' function will always return 'exists', no matter what function name you put in (for T-SQL). Insert entity if it doesn't exist, otherwise update. or you can add the save method into your delete and insert methods so it saves as it performs each one and you would only have to use two lines. Tests. Aug 24, 2015 · Because you create a new Address a new entity is created. Create(newCliente); cliente = rClientes. The database you want to delete would be listed under any of the localDB. NET 3. Jun 23, 2016 · The common way to remove entity in EF is the following: locate entity using DbSet<T>. This approach results in two SQL statements being executed: one to retrieve the entity from the database, and a second to delete it. In the BulkUpdate method, first, it fetches all the records whose LastName is Taylor and then updates the FirstName and StandardId properties values. Batch update/delete EF5; Answer. " - then analyze that. Aug 12, 2021 · Entity Framework Core (EF Core) represents relationships using foreign keys. Now i want to delete a record, but i can't delete from one table and not the other, when i try i get the following exception: 'A relationship is being added or deleted from an AssociationSet 'FK_lm_ab_profile_lm_profile_master'. Example: SELECT. Authors. The code works perfectly, but the part I need to add is a check to make sure that the ID passed does not exist before inserting it. Entity Framwork Core – Is a “Insert if not exists” possible? 4. 7. GetRequiredService<ApplicationDbContext>(); foreach (var c in countries) . The scenario is as follows: I have 3 tables which have the following flow: MainTeam -> UserPerTeam <- User. SingleOrDefault(s => s. Entity Framework Extensions library adds the BulkDelete extension method to the DbContext. In the regular delete, we are not modifying our entity but actually removing it from the database by using the Remove method or RemoveRange method for multiple entities: [HttpDelete(" {id}")] public IActionResult Delete(Guid id) {. 0, then the related end needs to be loaded before you set it to null. However, if the entities were already deleted (e. Col2) Error: Msg 4145, Level 15, State 1, Line 212 An expression of non-boolean type specified in a context where a condition is expected, near ','. This entity's foreign key value must match the primary key value (or an alternate key value) of the related principal/parent entity. An entity with a foreign key is the child or dependent entity in the relationship. ExecuteSqlCommand("drop if exists table myTableName"); May 9, 2013 · Entity framework is not very good at handling bulk operations like this. Insert(E2); Item. However there's a workaround. By calling the SaveChanges it will post the delete query to the database. ReportName == "Report". Empty); if your Id is Guid. Name is unique in the table in the database, you could do something like this narrow your list of nodes to ones that don't exist: var missingRecords = nodes. saying 0 rows were affected. What you want is a generic method to see if a record of an entity exists or not. There is no difference in deleting an entity in the connected and disconnected scenario in EF Core. Select SQL Server Object Explorer. return _baseRepository. select rows). Essentially, Cosmos DB has the functionality to set Time-to-Live (TTL) property on a container/document. Dec 4, 2021 · The DELETE becomes fun when the hard-delete needs to be implemented, meaning the records would be deleted from database table. The second issue is that two database accesses are required to accomplish the delete. 29. 1. In your situation I think it's best to use . Timestamp < {0}"; msdc. the controller accepts a List<T> and then stores this to a SQL database using AddRange. SaveChanges(); However, it takes a long time to execute. Deleted; foreach (var item in deleteMe. Remove(row); } dataDb. ToList (); Then insert the missing records with something like: context. When SaveChanges is called, a DELETE statement is generated and executed by the database. Any would return bool (true/false) if it finds any value that matches the condition. One of the commonly used approaches is to iterate each row and use the DBSet<T>. 5 SP1). If you don't know the Id, you can execute a query as I show below to find it first: var report= (from d in context. Currently, there's no cascading delete whatsoever. Check if list of entities already exist in Database using linq to entities. previous test run successfully cleaned up), ctx. Starting with EF Core 3. In addition, NO you don't have to load a document to delete it, that's jsut extra complexity, cost and roundtripto server. DeleteObject(entity) marks the entity as Deleted in the context. Copy. TypeId == 5). Quite expected. (It's EntityState is Deleted after that. Aug 15, 2022 · Sometimes, we may require to delete all the records from the table using Entity Framework Core. Feb 28, 2023 · saving. You can use Any() method of DBSet class, and pass it the condition to search for the record. The kind of think I'm looking for is class Program {. So you can implement an InsertOrUpdate() method as follows: As per the above figure, Entity Framework builds and executes INSERT, UPDATE, and DELETE statements for the entities whose EntityState is Added, Modified, or Deleted when the DbContext. g. BusinessTypeHiddenOptions. EntityTable. It is an unreliable check. Once you did, the document was found, and could be deleted. Sep 17, 2014 · To update an existing entity, all you need to do is set the tracking state to Modified. com Nov 1, 2022 · Console. Col1 AND a. Aug 21, 2013 · The entity won't be deleted from the database until you commit the transaction. So if you need to remove 10000 entities, then 10000 database round-trips will be performed which is INSANELY slow. Oct 18, 2019 · Here you need to chack with any primary key column value with your database record for existance of the record. ) If you call SaveChanges afterwards EF sends a SQL DELETE statement to the database. foreach ( var item in Db. Apr 11, 2023 · As explained in the CRUD tutorial, the Entity Framework implicitly implements transactions. However, this will result in two queries, if you need to process the record if it exists. foreach (T entity in theDbSet. Remove(report); The EntityEntry for the entity. Is there a way to check for references to this user before trying to delete or is the best option to just delete and catch/handle the exception that SaveChanges() throws? If you just need to check for the existence of a record, you can also use Any(). MyTable. Table. SaveChanges(); throws an Exception: Store update, insert, or delete statement affected an unexpected number of rows (0) That makes perfect sense, but just catching the Exception is a bit awkward. Strangely enough, my queries for retrieving Users no longer return it though. If function returns false it means no parent or child records and can be delete. Aug 22, 2014 · Here is the introduction, Introducing GraphDiff for Entity Framework Code First - Allowing automated updates of a graph of detached entities. ReadAsStringAsync (); var data = JsonConvert. The point that you need to remember is by default, cascade delete is enabled in Entity Framework for all types of relationships such Mar 29, 2023 · Information on saving graphs of related entities and managing relationships in Entity Framework Core I am using the code below to insert records into a SQL Server table. where d. The list is referenced by a unique Feb 6, 2016 · and use it as. If the entity has an EntityState. Deleting an entity is done using the Remove or RemoveRange method of the DbSet. You can define key in your entity model but the key must uniquely identify the record. To make the above a bit more straight forward, I wrote this simple extension method: public static void RemoveIfExists<T>( this DbSet<T>. Users) {. Jul 28, 2015 · As the example you show in your question, you need to load first the existing entity from your context to delete it. "it is not being deleted from the Database. Download or view the completed application. StudentReportDetail. Item. You can refer this post for the details. Added, it will be added to the database, if it has an EntityState. My Mainteam table has primary key ID is in relation with MainTeamID in table Jul 18, 2014 · "An object with the same key already exists in the ObjectStateManager. Alternatively, you can also set the entity state as Deleted. Remove(new Customer(Id: id)); // adds the object in "Deleted" state. it rd iz ko bz qj as ks rh kq