I'm using EntityFrameworkDataService in WCF service and I setup the rowguid and ModifiedData column in DB table. These values are generated by newid() and getdate() in DB. The problem is when I add new object from client application like below:
AddressType at = new AddressType();
at.Name = "home";
ccn.AddToAddressTypes(at);
ccn.SaveChanges();
It has an error. So If I add rowguid and ModifiedDate,
at.rowguid = Guid.NewGuid();
at.ModifiedDate = DateTime.Now;
It can add the object to the table. But I don't want to use the rowguid and modified value generated from the client side. I'd like to know how I have to handle the rowguid and modified value in EntityFrameworkDataService.
In your model diagram (.edmx), you have to change the StoreGeneratedPattern property from "None" to "Computed". It will solve this problem. Please see the more details at http://www.ladislavmrnka.com/2011/03/the-bug-in-storegeneratedpattern-fixed-in-vs-2010-sp1/
Related
I have the below model:
class Loan(models.Model):
id = models.BigAutoField(primary_key=True)
date = models.DateField(default=timezone.now)
description = models.TextField(max_length=255)
When I try to save date and description I get the above error
below is my admin.py file:
#admin.register(Loan)
class LoanAdmin(admin.ModelAdmin):
pass
and below is my table created through migrations:
Django 3.2.6.
How can I solve this?
SQL Server version is Microsoft SQL Server 2019 (RTM-CU8-GDR)
I tried :
class Loan(models.Model):
date = models.DateField(default=timezone.now)
description = models.TextField(max_length=255)
The solution that worked to this problem was to delete all migrations and create new migrations.
you don't need to add id column specifically. Django creates id column itself.
class Loan(models.Model):
date = models.DateField(default=timezone.now)
description = models.TextField(max_length=255)
This should work.
Also, if you want to add custom id column check this
Jdev Version : 11.1.1.7
I have created a Department VO based Department EO with the following query :
SELECT DeptEO.DEPARTMENT_ID,
DeptEO.DEPARTMENT_NAME,
DeptEO.MANAGER_ID,
DeptEO.LOCATION_ID,
DeptEO.ACTIVE
FROM DEPARTMENTS DeptEO where DeptEO.DEPARTMENT_ID > 250
UNION
SELECT 280 , 'Advertising',200,1700,'Y' from Dual
For the simplicity , I have used a sample statement from dual table , in real scenario , the query after UNION clause will populate from a table.
After running the query ,I get the result that is desired on the UI .
Now my requirement is to insert this newly created row with DEPARTMENT_ID as 280 , into DB table DEPARTMENTS.
While committing , ADF throws error as " oracle.jbo.RowAlreadyDeletedException: JBO-29114 " which is correct as the this row is missing from DB table , so when it goes for taking a lock on the row for update , it doesn't find anything .
Is there any way that i can instruct ADF to consider this row for Insert rather than update .
We also tried to populate the data of this row into a new row instance created from RowSetIterator , and afterwards remove the culprit row by calling removeFromCollection() and then inserting the duplicated row , but still no luck .
Other approaches that we are thinking of are :
1- Create another VO/EO and insert values in table through them .
2- Create a DB View for this query and trigger on this view , so when ever an update operation comes , we do our logic in trigger i.e. decide whether to update or insert the data.
Can you please guide what should be done in such scenario .
Regards,
Siddharth
Edit : Code for Inserting Row (What I was trying but it's not working)
RowSetIterator rsi=iterator.getRowSetIterator();
Row editableRow= rsi.createRow();
while(rsi.hasNext()){
Row r =rsi.next();
if((""+r.getAttribute("DepartmentId")).toString().equals("280") ){
System.err.println("? Equality row found!!!");
editableRow.setAttribute("DepartmentId", r.getAttribute("DepartmentId"));
editableRow.setAttribute("DepartmentName", r.getAttribute("DepartmentName"));
editableRow.setAttribute("ManagerId", r.getAttribute("ManagerId"));
editableRow.setAttribute("LocationId", r.getAttribute("LocationId"));
editableRow.setAttribute("Active", r.getAttribute("Active"));
rsi.removeCurrentRowFromCollection();
}
}
if(editableRow !=null){
System.err.println("? Row value after removal : "+editableRow.getAttribute("DepartmentName"));
rsi.insertRow(editableRow);
operBindingCommit.execute();
}
Your use case can be implemented in a couple of ways. First way is to iterate over row set in managed bean and check if department with id 280 exists, if yes then update the row otherwise invoke Create with parameters for department VO. The second way, and would say the better way, is to create a method for update/insert at business component level, either in ViewObjectImpl or in ApplicationModuleImpl and then invoke it from managed bean.
Here is the sample code for insert/update method written in VOImpl
public void updateInsertJobs(String jobId, String jobTitle,
String minSalary, String maxSalary)
{
RowSetIterator rSet = this.createRowSetIterator(null);
JobsViewRowImpl row = new JobsViewRowImpl();
Boolean jobExist = false;
if (null != jobId)
{
try
{
while (rSet.hasNext())
{
row = (JobsViewRowImpl) rSet.next();
if (row.getJobId().equals(jobId))
{
row.setJobTitle(jobTitle);
row.setMinSalary(new Number(minSalary));
row.setMaxSalary(new Number(maxSalary));
jobExist = true;
}
}
if (!jobExist)
{
JobsViewRowImpl r = (JobsViewRowImpl) this.createRow();
r.setJobId(jobId);
r.setJobTitle(jobTitle);
r.setMinSalary(new Number(minSalary));
r.setMaxSalary(new Number(maxSalary));
this.insertRow(r);
}
this.getDBTransaction().commit();
}
catch (Exception e)
{
e.printStackTrace();
}
}
}
Make sure to expose the method in Client Interface in order to be able to access it from data control.
Here is how to invoke the method from managed bean:
public void insertUpdateData(ActionEvent actionEvent)
{
BindingContainer bc =
BindingContext.getCurrent().getCurrentBindingsEntry();
OperationBinding oB = bc.getOperationBinding("updateInsertJobs");
oB.getParamsMap().put("jobId", "TI_STF");
oB.getParamsMap().put("jobTitle", "Technical Staff");
oB.getParamsMap().put("minSalary", "5000");
oB.getParamsMap().put("maxSalary", "18000");
oB.execute();
}
Some references which could be helpful:
http://mahmoudoracle.blogspot.com/2012/07/adf-call-method-from-pagedefinition.html#.VMLYaf54q-0
http://adftidbits.blogspot.com//2014/11/update-vo-data-programatically-adf.html
http://www.awasthiashish.com/2012/12/insert-new-row-in-adf-viewobject.html
Your view object become readonly due to custom sql query.
However you still can create row in dept table using entity.
Create java implemetation including accessors for DeptEO.
Create custom method in view object and create new entity or update existing using entity definition there. To find that required row exist, you can check that entity with this key is already exists. Something like this (assuming deptId is your primary key):
public void createOrUpdateDept(BigInteger deptId){
DeptEOImpl dept;
EntityDefImpl deptDef = DeptEOImpl.getDefinitionObject();
Key key = new Key(new Object[]{deptId});
dept = deptDef.findByPrimaryKey(getDBTransaction(), key);
if (dept == null){
// Creating new entity if it doesn't exist
dept = deptDef.createInstance2(getDBTransaction(), null);
dept.setDepartmentId(deptId);
}
// Changing other attributes
dept.setDepartmentName("New name");
// Commiting changes and refreshing ViewObject if required
getDBTransaction().commit();
executeQuery();
}
This code is just a sample, use it as reference/idea, don't blindly copy/paste.
I am creating an asp.net mvc4 site using entity framework 5 with codefirst and sql server express 2012.
I have enabled migrations and now do this in my Configuration.Seed method:
(note that I want to set the primary key to 8 even though this is the first record in the database).
context.ProductCategoryDtoes.AddOrUpdate(x => x.Id,
new ProductCategoryDto() { Id = 8, Name = "category1" }
);
My Model object is defined like this:
[Table("ProductCategory")]
public class ProductCategoryDto {
public long Id { get; set; }
public string Name { get; set; }
}
This results in a table in (SQL SERVER EXPRESS 2012) where the Id column has Identity = true, Identity seed = 1, identity increment = 1.
Now when I run migrations by doing an PM> Update-Database this result in a row with Id = 1.
So my question are:
1) How can I control the values of auto incremented primary keys when seeding data.
2) If the solution is to increment the key columns seed value, then how is this to be done when I am using Database.SetInitializer(new DropCreateDatabaseAlways<MyContext>());. This will nuke and rebuild the database everytime I update the database, so how would the seed value be updated in the fresh database?
Just create dummy entities with default values, then add your real data and afterwards delete the dummies. Not the best way but I guess there is no other...
Have you tried adding this on top of your Id property:
[DatabaseGenerated(DatabaseGeneratedOption.None)]
public long Id { get; set; }
It seems you are trying to defeat the purpose of an identity column. If you want to do this your only choice is to use SQL Commands Set IDENTITY_INSERT to allow you to insert the value and then run DBCC CHECKIDENT to update the seed. Not a really good idea. These options have security and performance limitations.
You may want to consider using a GUID instead. You can create GUIDs in code which are guaranteed to be unique, and you can also generate GUIDs in SQL as a column default.
With GUIDs, which are non sequential you will need to think through a good indexing strategy. This approach is also debatable.
Ultimately, it looks like you need a different strategy other than using an Identity Column.
It is very hackish, but I ran into a scenario where I had to do it due to some report having hard-coded PK values. Fixing the reports was beyond my scope of work.
Context.Database.ExecuteSqlCommand("SET IDENTITY_INSERT dbo.ProductCategoryDto ON " +
"INSERT INTO dbo.ProductCategoryDto (Id, Name) VALUES (8, 'category1') " +
"SET IDENTITY_INSERT dbo.ProductCategoryDto OFF");
I am trying to use Dapper support my data access for my server app.
My server app has another application that drops records into my database at a rate of 400 per minute.
My app pulls them out in batches, processes them, and then deletes them from the database.
Since data continues to flow into the database while I am processing, I don't have a good way to say delete from myTable where allProcessed = true.
However, I do know the PK value of the rows to delete. So I want to do a delete from myTable where Id in #listToDelete
Problem is that if my server goes down for even 6 mintues, then I have over 2100 rows to delete.
Since Dapper takes my #listToDelete and turns each one into a parameter, my call to delete fails. (Causing my data purging to get even further behind.)
What is the best way to deal with this in Dapper?
NOTES:
I have looked at Tabled Valued Parameters but from what I can see, they are not very performant. This piece of my architecture is the bottle neck of my system and I need to be very very fast.
One option is to create a temp table on the server and then use the bulk load facility to upload all the IDs into that table at once. Then use a join, EXISTS or IN clause to delete only the records that you uploaded into your temp table.
Bulk loads are a well-optimized path in SQL Server and it should be very fast.
For example:
Execute the statement CREATE TABLE #RowsToDelete(ID INT PRIMARY KEY)
Use a bulk load to insert keys into #RowsToDelete
Execute DELETE FROM myTable where Id IN (SELECT ID FROM #RowsToDelete)
Execute DROP TABLE #RowsToDelte (the table will also be automatically dropped if you close the session)
(Assuming Dapper) code example:
conn.Open();
var columnName = "ID";
conn.Execute(string.Format("CREATE TABLE #{0}s({0} INT PRIMARY KEY)", columnName));
using (var bulkCopy = new SqlBulkCopy(conn))
{
bulkCopy.BatchSize = ids.Count;
bulkCopy.DestinationTableName = string.Format("#{0}s", columnName);
var table = new DataTable();
table.Columns.Add(columnName, typeof (int));
bulkCopy.ColumnMappings.Add(columnName, columnName);
foreach (var id in ids)
{
table.Rows.Add(id);
}
bulkCopy.WriteToServer(table);
}
//or do other things with your table instead of deleting here
conn.Execute(string.Format(#"DELETE FROM myTable where Id IN
(SELECT {0} FROM #{0}s", columnName));
conn.Execute(string.Format("DROP TABLE #{0}s", columnName));
To get this code working, I went dark side.
Since Dapper makes my list into parameters. And SQL Server can't handle a lot of parameters. (I have never needed even double digit parameters before). I had to go with Dynamic SQL.
So here was my solution:
string listOfIdsJoined = "("+String.Join(",", listOfIds.ToArray())+")";
connection.Execute("delete from myTable where Id in " + listOfIdsJoined);
Before everyone grabs the their torches and pitchforks, let me explain.
This code runs on a server whose only input is a data feed from a Mainframe system.
The list I am dynamically creating is a list of longs/bigints.
The longs/bigints are from an Identity column.
I know constructing dynamic SQL is bad juju, but in this case, I just can't see how it leads to a security risk.
Dapper request the List of object having parameter as a property so in above case a list of object having Id as property will work.
connection.Execute("delete from myTable where Id in (#Id)", listOfIds.AsEnumerable().Select(i=> new { Id = i }).ToList());
This will work.
I have table with several fields, one of them is Id auto-increment/primary field. Is it possible to read new record Id field value after inserting new record using Linq to SQL?
Yes, the Id property will be set automatically when you call SubmitChanges. Example:
var customer = new Customer();
Console.WriteLine(customer.Id); // 0
context.Customers.InsertOnSubmit(customer); // Attach it to the context
context.SubmitChanges();
Console.WriteLine(customer.Id); // 1