I'm facing a problem that when I set a field any value than empty, EF will update the database.
But, when I clear the field (input[text] empty), the matching field in DB won't update to NULL.
Here are the codes:
C#
var entidade = new Plantas { CodPlanta = vm.CodPlanta };
db.Plantas.Attach(entidade);
entidade.CodEstado = vm.CodEstado;
entidade.NomePlanta = vm.NomePlanta;
entidade.CEP = vm.CEP;
entidade.Telefone = vm.Telefone;
entidade.Fax = vm.Fax;
db.SaveChanges();
SQL generated by EF
exec sp_executesql N'update [dbo].[Plantas]
set [CodEstado] = #0, [NomePlanta] = #1, [CEP] = #3
where ([CodPlanta] = #4)
',N'#0 int,#1 varchar(200),#3 char(8),#4 int',
#0=26,
#1='Apiaí',
#2='Integrada',
#3='18320000',
#4=373
go
See that when vm.Telefone and vm.Fax, these fields won't show in UPDATE query. But if a put some value, they will.
Even if the fields have some value before.
If a put a breakpoint at db.Savechanges(), it will show entidade.Telefone = null. But it won't go to the generated query.
How can I force Entity Framework to set fields to null?
The reason is that EF will only save modified fields. So if the field was null before you attach the object, and you set it to null again, EF will not update the database.
The solution is pretty simple: set the field to something other than null before you attach the object, than modify it to null before you save it.
One caveat: if you have optimistic concurrency control on the field, you may have to read the record from the database instead of attaching an empty object. Alternatively, use one column for optimistic concurrency control, such as a version number or SQL Server timestamp column.
For example, say you have this problem with the CEP column. Then do:
var entidade = new Plantas { CodPlanta = vm.CodPlanta };
entidade.CEP = "fake old value";
db.Plantas.Attach(entidade);
entidade.CEP = vm.CEP;
db.SaveChanges();
I found that setting attached instance of entity to "Modified" works:
db.Entry(entidade) = EntityState.Modified;
db.SaveChanges();
Related
I have lots of tables that contain default values, such as CreatedDateTime (getutcdate()). But right now, the value 0001-01-01 00:00:00.0000000 gets stored instead.
https://stackoverflow.com/a/35093135/7731479 --> that is not effective, I have to do it for each table manually for every database model update (edmx). How can I update all StoreGeneratedPattern to Computed automatically? Or why it does not takes computed automatically?
https://stackoverflow.com/a/43400053/7731479 --> ado.net generates all properties and I can't generate again CreatedDateTime.
Are there any automatic solution?
I am using Entity Framework and ado.net.
Person person = new Person()
{
Id = id,
Name = name,
};
AddToPerson(person);
SaveChanges();
I want to use above. I don't want use the following and assign CreatedDeteTime again because it is assigned in MSSQL with default value getutcdate().
Person person = new Person()
{
Id = id,
Name = name,
CreatedDeteTime = DateTime.UtcNow;
};
AddToPerson(person);
SaveChanges();
The configured default constraint of the SQL Server table will only be applied if you have a SQL INSERT statement that omits the column in question.
So if you insert
INSERT INTO dbo.Person(Id, Name) VALUES (42, "John Doe")
--> then your CreatedDateTime will automatically be set to the GETUTCDATE() value.
Unfortunately, if you have mapped this column in your EF model class, then this is not what happens. If you create an instance of Person in your C# code, and the CreatedDateTime column is in fact part of the model class, then EF will use something like this to insert the new person:
INSERT INTO dbo.Person(Id, Name, CreatedDateTime) VALUES (42, "John Doe", NULL)
and since now NULL is in fact provided for the CreatedDateTime column, that's the value that will be stored - or maybe it's an empty string - no matter what, the column is specified in the INSERT statement and thus the configured default constraint is not applied.
So if you want to let SQL Server kick in with the defaults, you need to make sure not to provide the column(s) in question in the INSERT statement at all. You can do this by:
having a separate model class just for inserts, which does not include those columns in question - e.g. have a NewPerson entity, that also maps to the Person table, but only consists of Name and ID for instance. Since those properties aren't there, EF cannot and will not generate an INSERT statement with them - so then the SQL Server default constraints will kick in
map the INSERT method to a SQL Server stored procedure and handle the inserting inside that procedure, by explicitly not specifying those columns you want to have take on default values
May be I'm wrong, but I have a question.
If you need to save a default date in your DB Table, why you're trying to save another date from programm level? I mean, it's easy to create a procedure and on the procedure level save the date. Something like (select getdate()...).
I have found two solutions:
1- This solution solve for all entities that has same property such as CreatedDateTime
public partial class MyEntities : ObjectContext
{
public override int SaveChanges(SaveOptions options)
{
this.DetectChanges();
foreach (var insert in this.ObjectStateManager.GetObjectStateEntries(System.Data.EntityState.Added))
{
if (insert.Entity.GetType().GetProperty("CreatedDateTime") != null && insert.Entity.GetType().GetProperty("CreatedDateTime").GetType().Name == "DateTime" && (DateTime)(insert.Entity.GetType().GetProperty("CreatedDateTime").GetValue(insert.Entity)) == DateTime.Parse("0001-01-01 00:00:00.0000000"))
insert.Entity.GetType().GetProperty("CreatedDateTime").SetValue(insert.Entity, DateTime.UtcNow, null);
}
return base.SaveChanges(options);
}
}
referance: https://stackoverflow.com/a/5965743/7731479
2-
public partial class Person
{
public Person()
{
this.CreatedDateTime = DateTime.UtcNow;
}
}
referance : DB default value ignored when creating Entity Framework model
I want to insert some records where I specify the Id, for the purpose of migrating data where I would like to maintain the integrity of existing relationships.
To do this I ran this command directly in SSMS on the table:
SET IDENTITY_INSERT [CRMTItem] ON;
Yet, when I insert an item from C# with Id of 1, the Id is still incrementing from around 850.
I deleted the entities from EDMX and updated again from DB but with the same result.
Here is my insert code, where as you can see I am ensuring that the Id is indeed 1 before inserting, yet this just gets ignored..
var crmtItem = new CRMTItem();
crmtItem.Id = adv.PrimaryId;
crmtItem.ProjectTitle = adv.ProjectTitle;
crmtItem.CreatedByUser = (adv.CreatedBy == null) ? (Guid?)null : new Guid(adv.CreatedBy);
crmtItem.Opportunity = (adv.Opportunity == null) ? (Guid?)null : new Guid(adv.Opportunity);
crmtItem.BidNoBid = adv.Bnb;
crmtItem.SPUrl = adv.SPUrl;
crmtItem.BnbId = (adv.BnbId == null) ? (Guid?)null : new Guid(adv.BnbId);
crmtItem.Stage = adv.ProjectStage;
crmtItem.Confidential = adv.Confidential;
crmtItem.OpportunityStatus = adv.OpportunityStatus;
crmtItem.OpportunityNumber = adv.OpportunityNumber;
crmtItem.CRMTNumber = adv.CrmtNumber;
crmtItem.ProjectNumber = adv.ProjectNumber;
crmtItem.Sector = adv.Sector;
crmtItem.Service = adv.Service;
crmtItem.CreatedDate = adv.CreatedDate;
crmtItem.Archive = adv.Archive;
crmtItem.ProjectManager = adv.ProjectManager;
crmtItem.WorkTeam = adv.WorkTeam;
crmtItem.Custodian = adv.Custodian;
db.CRMTItems.Add(crmtItem);
if (adv.PrimaryId == 1 || adv.PrimaryId == 2 || adv.PrimaryId == 3)
{
await db.SaveChangesAsync();
}
I also tried adding this line before inserting the item
db.Database.ExecuteSqlCommand("SET IDENTITY_INSERT [dbo].[CRMTItem] ON");
But it still doesn't work.
Based on another SO question I found, I tried this next:
db.Database.ExecuteSqlCommand("SET IDENTITY_INSERT [dbo].[CRMTItem] ON");
db.CRMTItems.Add(crmtItem);
if (adv.PrimaryId == 1)
{
await db.SaveChangesAsync();
}
db.Database.ExecuteSqlCommand("SET IDENTITY_INSERT [dbo].[CRMTItem] OFF");
transaction.Commit();
And now I get an error
Explicit value must be specified for identity column in table 'CRMTItem' either when IDENTITY_INSERT is set to ON or when a replication user is inserting into a NOT FOR REPLICATION identity column.
Am i missing something? Why must it be so difficult to control my own data? If I can't achieve this, I will be forced to creat a temporary column in my table just to store the id from the original (CDS) table, which is absolutely ridiculous, after all it is MY DATA, why can't I choose the value of the columns!?!?!
When you generate your model from database - Entity Framework will map all identity columns to model properties with StoreGeneratedPattern.Identity. In your case, such property is crmtItem.Id as I understand. When you insert crmItem - Entity Framework will ignore value you set for identity property (if you set any), because it knows this value is provided by database, so it knows if it tries to provide such value in insert statement - database will return an error.
Entity Framework has no knowledge of IDENTITY_INSERT, so it will always behave according to StoreGeneratedPattern metadata of target model property. If it's Identity or Computed - it will not provide value for it in insert, whatever you do. If it's set to None - then it will provide a value (no matter what).
So for your case you need to set this attribute to None in EDMX designer for target property (CRMTItem.Id). Of course after doing that - you will have to always provide this value while inserting.
Another part of the problem, with IDENTITY_INSERT being not respected, you already solved but still worth some explanation. This setting is session-scoped, so when you just execute it in SSMS and then try to insert from your application - it has no effect: SSMS and your application are in different sessions.
When you just do:
db.Database.ExecuteSqlCommand("SET IDENTITY_INSERT [dbo].[CRMTItem] ON");
This still executes in separate session, not in the same your SaveChanges will execute. So to execute both IDENTITY_INSERT and SaveChanges in the same session - you need to wrap them in transaction, as you already figured out.
I am working on Entity framework with database first approach and I came across below issue.
I have a Customer table with columns col1, col2, col3 ,....,col8. I have created an entity for this table and this table has around 100 records already. Out of above 8 columns, col4 is marked as Non-null.
Class Customer
{
member col1;
member col2;
member col3;
member col4;
.
.
member col8;
}
class Main
{
//main logic to read data from database using EF
Customer obj = object of Customerwith values assigned to col1,col2 and col3 members
obj.col2=some changed value.
DBContext.SaveChanges(); //<- throws an error stating it is expecting value of col4.
}
In my application, I am trying to read the one of the record using the stored procedure using EF and stored procedure only returns col1,col2 and col3.
I am trying to save the modified value of col2 and trying to save back to database using DBContext. But it thows an error stating value of required field col4 is not provided.
FYI: I have gone through couple of forums and question and option to go with disabled verfication on SaveChanges is not feasible for me.
Is there any other way through which I can achieve partial update?
I guess EntityFramework.Utilities satisfies your conditions.
This code:
using (var db = new YourDbContext())
{
db.AttachAndModify(new BlogPost { ID = postId }).Set(x => x.Reads, 10);
db.SaveChanges();
}
will generate single SQL command:
exec sp_executesql N'UPDATE [dbo].[BlogPosts]
SET [Reads] = #0
WHERE ([ID] = #1)
',N'#0 int,#1 int',#0=10,#1=1
disabled verfication on SaveChanges is not feasible for me
Sure it is. You even have to disable validation on Save. But then you can't mark the whole entity as modified, which I think you did. You must mark individual properties as modified:
var mySmallCustomer = someService.GetCustomer(); // from sproc
mySmallCustomer.col2 = "updated";
var myLargeCustomer = new Customer();
context.Customers.Attach(myLargeCustomer);
Entry(myLargeCustomer).CurrentValues.SetValues(mySmallCustomer);
// Here it comes:
Entry(myLargeCustomer).Property(c => c.col2).IsModified = true;
context.Configuration.ValidateOnSaveEnabled = false;
context.SaveChanges();
So you see it's enough to get the "small" customer. From this object you create a stub entity (myLargeCustomer) that is used for updating the one property.
I create a DNN(version 6.*) Module with LINQ to SQL. it was work by select operation and return true value, but in manipulate operation (update, insert, delete) when call SubmitChange() it not work:
SecurityLog dal = new SecurityLog()
{
Date = info.Date,
Description = info.Description,
UserIP = info.UserIP,
UserName = info.UserName
};
MyLogDataContext.CBI_SecurityLogs.InsertOnSubmit(dal);
MyLogDataContext.SubmitChanges();
although when i call SP binded method in DataContext it work complete.
MyLogDataContext.InsertSecurityLog(info.Date, info.UserName, info.Description, info.UserIP)
why it not work correct?
I don't see a Primary Key in your table. Linq needs a Primary Key defined to work.
Simply i wanna know
update table set (name,surname) values ('John','Locke') where Id=1
sql statment equivalent in llblgen, i tried below code but it didn't work.
Entity e = new Entity();
entity.Id = 1;
entity.name = "John";
entity.surname = "Locke";
entity.Save();
can anyone help?
Basically what you are doing above is creating a totally new entity. To update an existing one use this:
Entity e = new Entity(1);
entity.name = "John";
entity.surname = "Locke";
entity.Save();
The key is the first line. As you are using SelfServicing, in that line LLBLGen Framework will try to fetch the entity, if it exists on DB then the data is retrieved into the entity, otherwise the entity is treated as new. As the entity exists on DB, the values that are actually changed (i.e. the fetched field value is different from the one you actually set) will be used in the UPDATE sql query.
This is explained in the documentation.