Ако искате да създадете индекс и да ускорите заявката, добавете атрибута [Index] към атрибута и автоматично генерирайте кода по следния начин:
Актуализираме базата данни и грешката е следната:
System.Data.SqlClient.SqlException (0x80131904): table 'dbo. Колоната "Телефон" в "Сметка" не може да се използва като ключова колона в индекс.
at System.Data.SqlClient.SqlConnection.OnError (SqlException exception, Boolean breakConnection, Action'1 wrapCloseInAction)
at System.Data.SqlClient.SqlInternalConnection.OnError (SqlException exception, Boolean breakConnection, Action'1 wrapCloseInAction)
at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj, Boolean callerHasConnectionLock, Boolean asyncClose)
В System.Data.SqlClient.TdsParser.TryRun(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandleler, TdsParserStateObject stateObj, Boolean& dataReady)
at System.Data.SqlClient.SqlCommand.RunExecuteNonQueryTds(String methodName, Boolean async, Int32 timeout, Boolean asyncWrite)
В System.Data.SqlClient.SqlCommand.InternalExecuteNonQuery(TaskCompletionSource'1 completion, String methodName, Boolean sendToPipe, Int32 timeout, Boolean&usedCache, Boolean asyncWrite, булев в Retry)
В System.Data.SqlClient.SqlCommand.ExecuteNonQuery()
В System.Data.Entity.Infrastructure.Interception.DbCommandDispatcher. <NonQuery>b__0(DbCommand t, DbCommandInterceptionContext'1 c)
В System.Data.Entity.Infrastructure.Interception.InternalDispatcher'1.Dispatch[TTarget,TInterceptionContext,TResult](TTarget цел, Func'3 операция, TInterceptionContext interceptionContext, Action'3 изпълнява, Action'3 изпълнено)
В System.Data.Entity.Infrastructure.Interception.DbCommandDispatcher.NonQuery(DbCommand command, DbCommandInterceptionContext interceptionContext)
В System.Data.Entity.Internal.InterceptableDbCommand.ExecuteNonQuery()
В System.Data.Entity.Migrations.DbMigrator.ExecuteSql(MigrationStatement migrationStatement, DbConnection connection, DbTransaction transaction, DbInterceptionContext Интерсепшън Контекст)
В System.Data.Entity.Migrations.Infrastructure.MigratorLoggingDecorator.ExecuteSql(MigrationStatement migrationStatement, DbConnection connection, dbTransaction transaction , DbИнтерсепцияКонтекст на прихващанеКонтекст)
В System.Data.Entity.Migrations.DbMigrator.ExecuteStatementsInternal(IEnumerable'1 migrationStatements, DbConnection connection, DbTransaction transaction, DbИнтерсепцияКонтекст на прихващанеКонтекст)
В System.Data.Entity.Migrations.DbMigrator.ExecuteStatementsWithinTransaction(IEnumerable'1 migrationStatements, DbTransaction transaction, DbInterceptionContext Интерсепшън Контекст)
In System.Data.Entity.Migrations.DbMigrator.ExecuteStatementsWithinNewTransaction(IEnumerable'1 migrationStatements, DbConnection connection, DbInterceptionContext Интерсепшън Контекст)
В System.Data.Entity.Migrations.DbMigrator.ExecuteStatementsInternal(IEnumerable'1 migrationStatements, DbConnection connection, DbInterceptionContext interceptionContext)
at System.Data.Entity.Migrations.DbMigrator.ExecuteStatementsInternal(IEnumerable'1 migrationStatements, DbConnection connection)
в System.Data.Entity.Migrations.DbMigrator.<>c__DisplayClass32. <ExecuteStatements>b__30()
В System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.<>c__DisplayClass1. <Execute>b__0()
at System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute[TResult](Func'1 operation)
В System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute(Action operation)
В System.Data.Entity.Migrations.DbMigrator.ExecuteStatements(IEnumerable'1 migrationStatements, DbTransaction existingTransaction)
In System.Data.Entity.Migrations.DbMigrator.ExecuteStatements(IEnumerable'1 migrationStatements)
в System.Data.Entity.Migrations.Infrastructure.MigratorBase.ExecuteStatements(IEnumerable'1 migrationStatements)
В System.Data.Entity.Migrations.DbMigrator.ExecuteOperations(String migrationId, VersionedModel targetModel, IEnumerable'1 operations, IEnumerable'1 systemOperations, булев понижаване, булева авто-машина)
в System.Data.Entity.Migrations.DbMigrator.ApplyMigration(DbMigration, DbMigration lastMigration)
в System.Data.Entity.Migrations.Infrastructure.MigratorLoggingDecorator.ApplyMigration(DbMigration, DbMigration lastMigration)
в System.Data.Entity.Migrations.DbMigrator.Upgrade(IEnumerable'1 pendingMigrations, String targetMigrationId, String lastMigrationId)
at System.Data.Entity.Migrations.Infrastructure.MigratorLoggingDecorator.Upgrade(IEnumerable'1 pendingMigrations, String targetMigrationId, String lastMigrationId)
в System.Data.Entity.Migrations.DbMigrator.UpdateInternal(String targetMigration)
В System.Data.Entity.Migrations.DbMigrator.<>c__DisplayClasse. <Update>b__d()
в System.Data.Entity.Migrations.DbMigrator.EnsureDatabaseExists(Action mustSucceedToKeepDatabase)
в System.Data.Entity.Migrations.Infrastructure.MigratorBase.EnsureDatabaseExists(Action mustSucceedToKeepDatabase)
в System.Data.Entity.Migrations.DbMigrator.Update(String targetMigration)
В System.Data.Entity.Migrations.Infrastructure.MigratorBase.Update(String targetMigration)
в System.Data.Entity.Migrations.Design.ToolingFacade.UpdateRunner.RunCore()
В System.Data.Entity.Migrations.Design.ToolingFacade.BaseRunner.Run()
ClientConnectionId:2b5f614b-caab-4be6-bc1b-a813b7356739
Номер на грешка: 1919,Щат:1,Клас:16
Маса 'дбо. Колоната "Телефон" в "Сметка" не може да се използва като ключова колона в индекс.
Причината за грешката е, че всички низови свойства на ef са от тип NVARCHAR(Max) по подразбиране,
Решението е следното:
Изпълнете дължината на струната
Както е показано на снимката, творението е успешно!
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Публикувано в 23.11.2017 г. 18:47:15 ч.
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