EF Code First Update Database Encountered Error “There is already an object named 'Products' in the database”

问题

I'm using EF5 Code First in MVC4. There are tables where fields have decimal datatypes. I just wanted to update the precision of decimal originally from (18,2) to (18,4). Please help.

To achieve the goal I just modified the OnModelCreating something like this:

  protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {

            modelBuilder.Entity<DealerLevelDiscount>().Property(d =>d.Discount ).HasPrecision(18, 4);
            modelBuilder.Entity<DealerTransaction>().Property(d => d.ProductDiscount).HasPrecision(18, 4);
            modelBuilder.Entity<DealerTransaction>().Property(d => d.VolumeDiscount).HasPrecision(18, 4);
            modelBuilder.Conventions.Remove<OneToManyCascadeDeleteConvention>();

        }

Then I just ran:

PM> update-database -verbose command using Package Manager Console

But I got error:

There is already an object named 'Products' in the database.

Code Generated by Migration

PM> update-database -verbose
Using StartUp project 'SharkStore.WebUI'.
Using NuGet project 'SharkStore.Infrastructure'.
Specify the '-Verbose' flag to view the SQL statements being applied to the target database.
Target database is: 'SharkStore' (DataSource: (local), Provider: System.Data.SqlClient, Origin: Configuration).
Applying code-based migrations: [201304270821111_InitialCreate, 201305041132116_updateDatabae, 201305111219416_5112013, 201305141351533_5142013, 201305231451514_5232013, 201306130611074_06132013_updates, 201306221339425_06222013, 201306231051456_06232013, 201306251538120_06251013, 201306251611006_06262013_01, 201307021414262_07022013, 201307040902338_742013, 201307140659150_07142013, 201307140701597_07142013_1, 201308050843017_852013, 201309270307238_09272013].
Applying code-based migration: 201304270821111_InitialCreate.
CREATE TABLE [dbo].[Products] (
    [Id] [int] NOT NULL IDENTITY,
    [Thumbnail] [nvarchar](max),
    [MainImage] [nvarchar](max),
    [FileData] [nvarchar](max),
    [Name] [nvarchar](max),
    [ShortDescription] [nvarchar](max),
    [LongDescription] [nvarchar](max),
    [Price] [decimal](18, 2) NOT NULL,
    [DownloadCount] [int] NOT NULL,
    [BHMinVersion] [nvarchar](max),
    [BHMinEdition] [nvarchar](max),
    [TrialPeriod] [int] NOT NULL,
    [ProductTypeId] [int] NOT NULL,
    [CreatedBy] [int] NOT NULL,
    [IsDeleted] [bit] NOT NULL,
    [ModifiedBy] [int] NOT NULL,
    [CreatedDate] [datetime],
    [ModifiedDate] [datetime],
    CONSTRAINT [PK_dbo.Products] PRIMARY KEY ([Id])
)

Migration Table

Stacktrace

System.Data.SqlClient.SqlException (0x80131904): There is already an object named 'Products' in the database.
   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)
   at System.Data.SqlClient.TdsParser.TryRun(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj, Boolean& dataReady)
   at System.Data.SqlClient.SqlCommand.RunExecuteNonQueryTds(String methodName, Boolean async, Int32 timeout)
   at System.Data.SqlClient.SqlCommand.InternalExecuteNonQuery(TaskCompletionSource`1 completion, String methodName, Boolean sendToPipe, Int32 timeout, Boolean asyncWrite)
   at System.Data.SqlClient.SqlCommand.ExecuteNonQuery()
   at System.Data.Entity.Migrations.DbMigrator.ExecuteSql(DbTransaction transaction, MigrationStatement migrationStatement)
   at System.Data.Entity.Migrations.Infrastructure.MigratorLoggingDecorator.ExecuteSql(DbTransaction transaction, MigrationStatement migrationStatement)
   at System.Data.Entity.Migrations.DbMigrator.ExecuteStatements(IEnumerable`1 migrationStatements)
   at System.Data.Entity.Migrations.Infrastructure.MigratorBase.ExecuteStatements(IEnumerable`1 migrationStatements)
   at System.Data.Entity.Migrations.DbMigrator.ExecuteOperations(String migrationId, XDocument targetModel, IEnumerable`1 operations, Boolean downgrading, Boolean auto)
   at System.Data.Entity.Migrations.DbMigrator.ApplyMigration(DbMigration migration, DbMigration lastMigration)
   at System.Data.Entity.Migrations.Infrastructure.MigratorLoggingDecorator.ApplyMigration(DbMigration migration, DbMigration lastMigration)
   at 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)
   at System.Data.Entity.Migrations.DbMigrator.Update(String targetMigration)
   at System.Data.Entity.Migrations.Infrastructure.MigratorBase.Update(String targetMigration)
   at System.Data.Entity.Migrations.Design.ToolingFacade.UpdateRunner.RunCore()
   at System.Data.Entity.Migrations.Design.ToolingFacade.BaseRunner.Run()
ClientConnectionId:bcd5bb53-2e1d-4121-8aae-4ebfe353ebf6

回答1:

I was having the same issue and after trying to add new migrations and update the database schema with them, without success, I deleted all the migration source files and I deleted the migration entries rows found on the dbo_MigrationHistory table. After that I added a new migration and was able to update schema changes.

I hope this help.

回答2:

This might be late, but the above answer did not solve my problem but manually dropping all the tables and then using update-database -forcein the package manager console did the job for me......

来源：https://stackoverflow.com/questions/19542462/ef-code-first-update-database-encountered-error-there-is-already-an-object-name