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Description
Description
There is an issue when adding new entities of different types to the context and calling save changes at the end when one entity only has a single record to add and another entity has more than two records to add. I followed a variation of this example to produce the issue, and have included the demo application for reproducing the problem.
Problem Code Snippet
var students = new Student[]
{
new Student{FirstMidName="Carson",LastName="Alexander",EnrollmentDate=DateTime.Parse("2019-09-01")},
new Student{FirstMidName="Meredith",LastName="Alonso",EnrollmentDate=DateTime.Parse("2017-09-01")},
new Student{FirstMidName="Arturo",LastName="Anand",EnrollmentDate=DateTime.Parse("2018-09-01")},
new Student{FirstMidName="Gytis",LastName="Barzdukas",EnrollmentDate=DateTime.Parse("2017-09-01")},
new Student{FirstMidName="Yan",LastName="Li",EnrollmentDate=DateTime.Parse("2017-09-01")},
new Student{FirstMidName="Peggy",LastName="Justice",EnrollmentDate=DateTime.Parse("2016-09-01")},
new Student{FirstMidName="Laura",LastName="Norman",EnrollmentDate=DateTime.Parse("2018-09-01")},
new Student{FirstMidName="Nino",LastName="Olivetto",EnrollmentDate=DateTime.Parse("2019-09-01")}
};
// SUCCESS - Works whenever there is more than one student being added and a collection of courses are added.
// context.Students.AddRange(students);
// OR
// context.Students.Add(students[0]);
// context.Students.Add(students[1]);
// FAILS - Fails whenever there is only one student being added and three or more courses being added to the context at the same time.
// context.Students.AddRange(students[0]);
// OR
context.Students.Add(students[0]);
var courses = new Course[]
{
new Course{Title="Chemistry",Credits=3},
new Course{Title="Microeconomics",Credits=3},
new Course{Title="Macroeconomics",Credits=3},
new Course{Title="Calculus",Credits=4},
new Course{Title="Trigonometry",Credits=4},
new Course{Title="Composition",Credits=3},
new Course{Title="Literature",Credits=4}
};
// NOTE: If you add a single student and only two courses, then save changes will succeed.
context.Courses.AddRange(courses);
// Save changes must be called at the end to have both types of entities saved to the database at the same time for this issue to occur.
context.SaveChanges();Stack trace
Exception: An error occurred while saving the entity changes. See the inner exception for details.
at Microsoft.EntityFrameworkCore.Update.ReaderModificationCommandBatch.Execute(IRelationalConnection connection)
at Microsoft.EntityFrameworkCore.Update.Internal.BatchExecutor.Execute(IEnumerable`1 commandBatches, IRelationalConnection connection)
at Microsoft.EntityFrameworkCore.Storage.RelationalDatabase.SaveChanges(IList`1 entries)
at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChanges(IList`1 entriesToSave)
at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChanges(StateManager stateManager, Boolean acceptAllChangesOnSuccess)
at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.<>c.<SaveChanges>b__104_0(DbContext _, ValueTuple`2 t)
at Microsoft.EntityFrameworkCore.SqlServer.Storage.Internal.SqlServerExecutionStrategy.Execute[TState,TResult](TState state, Func`3 operation, Func`3 verifySucceeded)
at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChanges(Boolean acceptAllChangesOnSuccess)
at Microsoft.EntityFrameworkCore.DbContext.SaveChanges(Boolean acceptAllChangesOnSuccess)
at Microsoft.EntityFrameworkCore.DbContext.SaveChanges()
at Sample.Api.Data.DbInitializer.Initialize(SchoolContext context) in C:\source\repos\Sample.Api\Sample.Api\Data\DbInitializer.cs:line 62
at Program.<Main>$(String[] args) in C:\source\repos\Sample.Api\Sample.Api\Program.cs:line 35
Inner Exception: The variable name '@instered0' has already been declared. Variable names must be unique withing a query batch or stored procedure.
at Microsoft.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection, Action`1 wrapCloseInAction)
at Microsoft.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection, Action`1 wrapCloseInAction)
at Microsoft.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj, Boolean callerHasConnectionLock, Boolean asyncClose)
at Microsoft.Data.SqlClient.TdsParser.TryRun(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj, Boolean& dataReady)
at Microsoft.Data.SqlClient.SqlDataReader.TryConsumeMetaData()
at Microsoft.Data.SqlClient.SqlDataReader.get_MetaData()
at Microsoft.Data.SqlClient.SqlCommand.FinishExecuteReader(SqlDataReader ds, RunBehavior runBehavior, String resetOptionsString, Boolean isInternal, Boolean forDescribeParameterEncryption, Boolean shouldCacheForAlwaysEncrypted)
at Microsoft.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean isAsync, Int32 timeout, Task& task, Boolean asyncWrite, Boolean inRetry, SqlDataReader ds, Boolean describeParameterEncryptionRequest)
at Microsoft.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, TaskCompletionSource`1 completion, Int32 timeout, Task& task, Boolean& usedCache, Boolean asyncWrite, Boolean inRetry, String method)
at Microsoft.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method)
at Microsoft.Data.SqlClient.SqlCommand.ExecuteReader(CommandBehavior behavior)
at Microsoft.Data.SqlClient.SqlCommand.ExecuteDbDataReader(CommandBehavior behavior)
at System.Data.Common.DbCommand.ExecuteReader()
at Microsoft.EntityFrameworkCore.Storage.RelationalCommand.ExecuteReader(RelationalCommandParameterObject parameterObject)
at Microsoft.EntityFrameworkCore.Update.ReaderModificationCommandBatch.Execute(IRelationalConnection connection)
Include provider and version information
EF Core version: 6.0.0
Database provider: Microsoft.EntityFrameworkCore.SqlServer
Target framework: .NET 6.0
Operating system: Windows 11 Pro
IDE: Visual Studio Enterprise 2022 (64-bit) 17.0.0
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