.net EF 4.3.1迁移异常-AlterColumn defaultValueSql为不同的表创建相同的默认约束名称
我有一个使用OOB数据库初始值设定项创建的DB,我首先使用EF4.3.1中的代码 我想利用Add-Migration cmdlet上新的“IgnoreChanges”标志,以便可以更改一些列并添加默认SQL值。本质上,我的一些实体有一个名为DateLastUpdated的列,我想将其默认设置为sql表达式GETDATE() 我使用“add migration InitialMigration-ignorechanges”创建了InitialMigration,然后将以下内容添加到Up()和Down() 然后我尝试运行“updatedatabase-verbose”,但我看到它试图在数据库上创建相同的命名默认约束,SQL抛出一个异常:.net EF 4.3.1迁移异常-AlterColumn defaultValueSql为不同的表创建相同的默认约束名称,.net,entity-framework,entity-framework-4.3,entity-framework-migrations,.net,Entity Framework,Entity Framework 4.3,Entity Framework Migrations,我有一个使用OOB数据库初始值设定项创建的DB,我首先使用EF4.3.1中的代码 我想利用Add-Migration cmdlet上新的“IgnoreChanges”标志,以便可以更改一些列并添加默认SQL值。本质上,我的一些实体有一个名为DateLastUpdated的列,我想将其默认设置为sql表达式GETDATE() 我使用“add migration InitialMigration-ignorechanges”创建了InitialMigration,然后将以下内容添加到Up()和Dow
Applying explicit migrations: [201203221856095_InitialMigration].
Applying explicit migration: 201203221856095_InitialMigration.
ALTER TABLE [CustomerLocations] ADD CONSTRAINT DF_DateLastUpdated DEFAULT GETDATE() FOR [DateLastUpdated]
ALTER TABLE [CustomerLocations] ALTER COLUMN [DateLastUpdated] [datetime]
ALTER TABLE [UserReportTemplates] ADD CONSTRAINT DF_DateLastUpdated DEFAULT GETDATE() FOR [DateLastUpdated]
System.Data.SqlClient.SqlException (0x80131904): There is already an object named 'DF_DateLastUpdated' in the database.
Could not create constraint. See previous errors.
at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection)
at System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection)
at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning()
at System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj)
at System.Data.SqlClient.SqlCommand.RunExecuteNonQueryTds(String methodName, Boolean async)
at System.Data.SqlClient.SqlCommand.InternalExecuteNonQuery(DbAsyncResult result, String methodName, Boolean sendToPipe)
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)
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()
There is already an object named 'DF_DateLastUpdated' in the database.
Could not create constraint. See previous errors.
看起来EF正在创建默认约束,方法是将“DF_3;”与列的名称一起添加,但不使用表的名称,以使其对表唯一。这是一个已知的错误,还是我在这里做错了什么?这似乎是一个已知的错误: 安德鲁·彼得斯(Andrew J Peters)微软公司(MSFT)回答说: 谢谢你的报道。RTM将解决该问题 一种可能的解决方法是首先使列为null,这 将阻止迁移生成额外的默认约束。 创建列后,可以将其更改回 不可为空 但在EF 4.3.1中,它并没有被确定。以下是资料来源的相关部分:
// Type: System.Data.Entity.Migrations.Sql.SqlServerMigrationSqlGenerator
// Assembly: EntityFramework, Version=4.3.1.0,
// Culture=neutral, PublicKeyToken=b77a5c561934e089
namespace System.Data.Entity.Migrations.Sql
{
public class SqlServerMigrationSqlGenerator : MigrationSqlGenerator
{
protected virtual void Generate(AlterColumnOperation alterColumnOperation)
{
//...
writer.Write("ALTER TABLE ");
writer.Write(this.Name(alterColumnOperation.Table));
writer.Write(" ADD CONSTRAINT DF_");
writer.Write(column.Name);
writer.Write(" DEFAULT ");
//...
因此EF不会试图使约束名称唯一
您应该尝试解决方法并将其报告为bug
编辑:
我刚刚意识到上面提到的Generate
方法是virtual
,因此在最坏的情况下,您可以从SqlServerMigrationSqlGenerator
继承并修复SQL生成,并将其设置为Configuration.cs中的SQL生成器:
public Configuration()
{
AutomaticMigrationsEnabled = true;
SetSqlGenerator("System.Data.SqlClient",
new MyFixedSqlServerMigrationSqlGenerator());
}
编辑2:
我认为最好的办法是,在它恢复到原始SQL之前:
public override void Up()
{
Sql(@"ALTER TABLE [CustomerLocations] ADD CONSTRAINT
DF_CustomerLocations_DateLastUpdated
DEFAULT GETDATE() FOR [DateLastUpdated]");
Sql(@"ALTER TABLE [CustomerLocations] ALTER COLUMN
[DateLastUpdated] [datetime]");
//...
}
好的,根据nemesv的回答(已接受),以下是我现在如何解决问题,直到正式发布解决方案:
internal class MyFixedSqlServerMigrationSqlGenerator : SqlServerMigrationSqlGenerator
{
protected override void Generate(AlterColumnOperation alterColumnOperation)
{
if (alterColumnOperation == null)
throw new ApplicationException("alterColumnOperation != null");
ColumnModel column = alterColumnOperation.Column;
if ((column.DefaultValue != null) || !string.IsNullOrWhiteSpace(column.DefaultValueSql))
{
using (IndentedTextWriter writer = Writer())
{
writer.Write("ALTER TABLE ");
writer.Write(this.Name(alterColumnOperation.Table));
writer.Write(" ADD CONSTRAINT DF_");
writer.Write(alterColumnOperation.Table + "_"); // <== THIS IS THE LINE THAT FIXES THE PROBLEM
writer.Write(column.Name);
writer.Write(" DEFAULT ");
writer.Write(column.DefaultValue != null ? base.Generate(column.DefaultValue) : column.DefaultValueSql);
writer.Write(" FOR ");
writer.Write(this.Quote(column.Name));
this.Statement(writer);
}
}
using (IndentedTextWriter writer2 = Writer())
{
writer2.Write("ALTER TABLE ");
writer2.Write(this.Name(alterColumnOperation.Table));
writer2.Write(" ALTER COLUMN ");
writer2.Write(this.Quote(column.Name));
writer2.Write(" ");
writer2.Write(this.BuildColumnType(column));
if (column.IsNullable.HasValue && !column.IsNullable.Value)
{
writer2.Write(" NOT NULL");
}
this.Statement(writer2);
}
}
}
internal sealed class Configuration : DbMigrationsConfiguration<MyDbContext>
{
public Configuration()
{
AutomaticMigrationsEnabled = true;
SetSqlGenerator("System.Data.SqlClient", new MyFixedSqlServerMigrationSqlGenerator());
}
...
}
内部类MyFixedSqlServerMigrationSqlGenerator:SqlServerMigrationSqlGenerator
{
受保护的覆盖无效生成(AlterColumnOperation AlterColumnOperation)
{
if(alterColumnOperation==null)
抛出新的ApplicationException(“alterColumnOperation!=null”);
ColumnModel column=alterColumnOperation.column;
if((column.DefaultValue!=null)| |!string.IsNullOrWhiteSpace(column.DefaultValueSql))
{
使用(IndentedTextWriter=writer())
{
writer.Write(“更改表”);
writer.Write(this.Name(alterColumnOperation.Table));
writer.Write(“添加约束DF_”);
Write(alterColumnOperation.Table+“”)/此解决方案在EF 6.1.3中进行了测试。很可能适用于以前的版本
您可以从System.Data.Entity.SqlServer命名空间实现从SqlServerMigrationSqlGenerator派生的自定义sql生成器类:
using System.Data.Entity.Migrations.Model;
using System.Data.Entity.SqlServer;
namespace System.Data.Entity.Migrations.Sql{
internal class FixedSqlServerMigrationSqlGenerator : SqlServerMigrationSqlGenerator {
protected override void Generate(AlterColumnOperation alterColumnOperation){
ColumnModel column = alterColumnOperation.Column;
var sql = String.Format(@"DECLARE @ConstraintName varchar(1000);
DECLARE @sql varchar(1000);
SELECT @ConstraintName = name FROM sys.default_constraints
WHERE parent_object_id = object_id('{0}')
AND col_name(parent_object_id, parent_column_id) = '{1}';
IF(@ConstraintName is NOT Null)
BEGIN
set @sql='ALTER TABLE {0} DROP CONSTRAINT [' + @ConstraintName+ ']';
exec(@sql);
END", alterColumnOperation.Table, column.Name);
this.Statement(sql);
base.Generate(alterColumnOperation);
return;
}
protected override void Generate(DropColumnOperation dropColumnOperation){
var sql = String.Format(@"DECLARE @SQL varchar(1000)
SET @SQL='ALTER TABLE {0} DROP CONSTRAINT [' + (SELECT name
FROM sys.default_constraints
WHERE parent_object_id = object_id('{0}')
AND col_name(parent_object_id, parent_column_id) = '{1}') + ']';
PRINT @SQL;
EXEC(@SQL); ", dropColumnOperation.Table, dropColumnOperation.Name);
this.Statement(sql);
base.Generate(dropColumnOperation);
}
}
}
并设置此配置:
internal sealed class Configuration : DbMigrationsConfiguration<MyDbContext>
{
public Configuration()
{
AutomaticMigrationsEnabled = true;
SetSqlGenerator("System.Data.SqlClient", new FixedSqlServerMigrationSqlGenerator ());
}
...
}
内部密封类配置:dbmigtorinsconfiguration
{
公共配置()
{
AutomaticMiggerationsEnabled=真;
SetSqlGenerator(“System.Data.SqlClient”,新的FixedSqlServerMigrationSqlGenerator());
}
...
}
你从哪里获得EF的代码?我使用的是Reflector,但该生成方法的一部分可能使用了大量lambda、funcs/actions和匿名内容,因此Reflector没有给我一个好的版本来复制和修改。我在Resharper中使用了内置反编译程序(你可以使用免费的Jetbrains反编译程序)Telerik的JustDecompile也生成了几乎相同的源代码。但两者都包含大量lambad:(因此它不能直接重用。@ThiagoSilva我认为最简单的方法是用原始SQL编写这种迁移,直到这个错误修复。我已经更新了我的答案。一年后,在EF5中仍然没有修复。现在似乎已经修复了。根据我遇到的问题,alterColumnOpe,这些约束被命名为DF_tableName_columnNameration.Table
包含架构,导致约束的名称无效(如'DF_dbo.MyTable_MyColumn')。我使用此帮助器方法修复了它:private string RemoveSchema(string name){return name.Split('.').Last();}
不知道是否更安全,但如果他们更改默认EF方法,而不是使用IndentedTextWriter…
块更改第二个,您可以将默认值设置为null
并让基方法完成子句的创建:column.DefaultValue=null;column.DefaultValueSql=null;base.Generate(alterColumnOperation);
检查Elyas的答案。这是一个很好的解决方案
internal sealed class Configuration : DbMigrationsConfiguration<MyDbContext>
{
public Configuration()
{
AutomaticMigrationsEnabled = true;
SetSqlGenerator("System.Data.SqlClient", new FixedSqlServerMigrationSqlGenerator ());
}
...
}