C# 在.net core 2中为多个表插入标识\u
我正在尝试将数据从现有数据库迁移到新数据库。旧数据库非常复杂,这意味着大多数表都与许多其他基于外来ID的表有关系。我遇到了一个插入ID的解决方案:C# 在.net core 2中为多个表插入标识\u,c#,sql-server,entity-framework,asp.net-core-2.0,C#,Sql Server,Entity Framework,Asp.net Core 2.0,我正在尝试将数据从现有数据库迁移到新数据库。旧数据库非常复杂,这意味着大多数表都与许多其他基于外来ID的表有关系。我遇到了一个插入ID的解决方案: using (var context = new EmployeeContext()) { context.Employees.Add(new Employee { EmployeeId = 100, Name = "John Doe" }); context.Employees.Add(new Employee { Employee
using (var context = new EmployeeContext())
{
context.Employees.Add(new Employee { EmployeeId = 100, Name = "John Doe" });
context.Employees.Add(new Employee { EmployeeId = 101, Name = "Jane Doe" });
context.Database.OpenConnection();
try
{
context.Database.ExecuteSqlCommand("SET IDENTITY_INSERT dbo.Employees ON");
context.SaveChanges();
context.Database.ExecuteSqlCommand("SET IDENTITY_INSERT dbo.Employees OFF");
}
finally
{
context.Database.CloseConnection();
}
foreach (var employee in context.Employees)
{
Console.WriteLine(employee.EmployeeId + ": " + employee.Name);
}
}
从本Microsoft指南:
在应用
context.SaveChanges()之前,是否有方法在多个表上设置IDENTITY\u INSERT
代码>?不。查看IDENTITY_INSERT的文档
它明确指出:
在任何时候,会话中只有一个表可以具有标识\u INSERT
属性设置为ON。如果表已将此属性设置为“开”,
并为另一个表发出SET IDENTITY_INSERT ON语句,
SQL Server返回一条错误消息,指出SET IDENTITY\u INSERT为
已启用,并报告为其设置的表
没有。查看IDENTITY_INSERT的文档
它明确指出:
在任何时候,会话中只有一个表可以具有标识\u INSERT
属性设置为ON。如果表已将此属性设置为“开”,
并为另一个表发出SET IDENTITY_INSERT ON语句,
SQL Server返回一条错误消息,指出SET IDENTITY\u INSERT为
已启用,并报告为其设置的表
我在这里遇到了同样的问题,当时我从存储在json文件中的对象树中播种数据
例如:
jsonData = System.IO.File.ReadAllText(@"Data\InputParameters.json");
var inputParameters = JsonConvert.DeserializeObject<List<ParameterCategory>> jsonData, settings);
context.AddRange(inputParameters);
context.SaveChanges();
jsonData=System.IO.File.ReadAllText(@“Data\InputParameters.json”);
var inputParameters=JsonConvert.DeserializeObject jsonData,设置);
AddRange(inputParameters);
SaveChanges();
在查看了EFCore源代码后,我提出了以下解决方案:
1。创建一个新类“SQLServerUpdateSqlGeneratorInCertidentity”,该类负责为每个插入操作打开和关闭标识插入:
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.EntityFrameworkCore.SqlServer.Update.Internal;
using Microsoft.EntityFrameworkCore.Storage;
using Microsoft.EntityFrameworkCore.Update;
/// <summary>
/// SqlServerUpdateSqlGenerator with Insert_Identity.
/// </summary>
public class SqlServerUpdateSqlGeneratorInsertIdentity : SqlServerUpdateSqlGenerator
{
/// <summary>
/// Initializes a new instance of the <see cref="SqlServerUpdateSqlGeneratorInsertIdentity"/> class.
/// </summary>
/// <param name="dependencies">The dependencies.</param>
public SqlServerUpdateSqlGeneratorInsertIdentity(UpdateSqlGeneratorDependencies dependencies)
: base(dependencies)
{
}
/// <inheritdoc/>
public override ResultSetMapping AppendBulkInsertOperation(
StringBuilder commandStringBuilder,
IReadOnlyList<ModificationCommand> modificationCommands,
int commandPosition)
{
var columns = modificationCommands[0].ColumnModifications.Where(o => o.IsWrite).Select(o => o.ColumnName)
.ToList();
var schema = modificationCommands[0].Schema;
var table = modificationCommands[0].TableName;
GenerateIdentityInsert(commandStringBuilder, table, schema, columns, on: true);
var result = base.AppendBulkInsertOperation(commandStringBuilder, modificationCommands, commandPosition);
GenerateIdentityInsert(commandStringBuilder, table, schema, columns, on: false);
return result;
}
private void GenerateIdentityInsert(
StringBuilder builder,
string table,
string schema,
IEnumerable<string> columns,
bool on)
{
var stringTypeMapping = Dependencies.TypeMappingSource.GetMapping(typeof(string));
builder.Append("IF EXISTS (SELECT * FROM [sys].[identity_columns] WHERE").Append(" [name] IN (")
.Append(string.Join(", ", columns.Select(stringTypeMapping.GenerateSqlLiteral)))
.Append(") AND [object_id] = OBJECT_ID(").Append(
stringTypeMapping.GenerateSqlLiteral(
Dependencies.SqlGenerationHelper.DelimitIdentifier(table, schema))).AppendLine("))");
builder.Append("SET IDENTITY_INSERT ")
.Append(Dependencies.SqlGenerationHelper.DelimitIdentifier(table, schema)).Append(on ? " ON" : " OFF")
.AppendLine(Dependencies.SqlGenerationHelper.StatementTerminator);
}
}
使用System.Collections.Generic;
使用System.Linq;
使用系统文本;
使用Microsoft.EntityFrameworkCore.SqlServer.Update.Internal;
使用Microsoft.EntityFrameworkCore.Storage;
使用Microsoft.EntityFrameworkCore.Update;
///
///SqlServerUpdateSqlGenerator具有Insert_标识。
///
公共类SQLServerUpdateSqlGeneratorInEntity:SqlServerUpdateSqlGenerator
{
///
///初始化类的新实例。
///
///依赖关系。
公共SqlServerUpdateSqlGeneratorInsertIdentity(UpdateSqlGeneratorDependencies依赖项)
:base(依赖项)
{
}
///
公共覆盖结果映射AppendBulkInsertOperation(
StringBuilder命令StringBuilder,
IReadOnlyList修改命令,
int命令位置)
{
var columns=modificationCommands[0]。ColumnModifications.Where(o=>o.IsWrite)。选择(o=>o.ColumnName)
.ToList();
var schema=modificationCommands[0]。架构;
var table=modificationCommands[0]。TableName;
GenerateIdentityInsert(commandStringBuilder、表、架构、列、on:true);
var result=base.AppendBulkInsertOperation(commandStringBuilder、modificationCommands、commandPosition);
GenerateIdentityInsert(commandStringBuilder、表、架构、列、on:false);
返回结果;
}
私有void GenerateIdentityInsert(
StringBuilder,
字符串表,
字符串模式,
IEnumerable列,
(开玩笑)
{
var stringTypeMapping=Dependencies.TypeMappingSource.GetMapping(typeof(string));
builder.Append(“如果存在(从[sys].[identity\u columns]WHERE]中选择*)。Append(“[name]”在(“)
.Append(string.Join(“,”,columns.Select(stringTypeMapping.GenerateSqlLiteral)))
.Append(“)和[object\u id]=object\u id(“).Append(
stringTypeMapping.GenerateSqlLiteral(
Dependencies.SqlGenerationHelper.differentifier(表、模式)).AppendLine(“)”;
builder.Append(“设置标识\u插入”)
.Append(Dependencies.SqlGenerationHelper.differentifier(表、架构)).Append(开?:“关”)
.AppendLine(Dependencies.SqlGenerationHelper.StatementTerminator);
}
}
2.用继承的新“SqlServerUpdateSqlGenerator”替换原来的“SqlServerUpdateSqlGenerator”:
在Startup.cs-ConfigureServices中,使用以下代码:
services.AddDbContext<YourDataContext>(options =>
{
options.UseSqlServer(YourConnectionString);
options.ReplaceService<ISqlServerUpdateSqlGenerator, SqlServerUpdateSqlGeneratorInsertIdentity>();
});
services.AddDbContext(选项=>
{
选项。使用SQLServer(您的连接字符串);
options.ReplaceService();
});
或在YourDataContext.cs中-on配置使用此选项(未测试):
options.ReplaceService();
播种后,可能需要将服务配置重置为原始配置。就我而言,它不是
希望这能帮助某人…我在这里遇到了同样的问题,当时我正在从存储在json文件中的对象树中播种数据
例如:
jsonData = System.IO.File.ReadAllText(@"Data\InputParameters.json");
var inputParameters = JsonConvert.DeserializeObject<List<ParameterCategory>> jsonData, settings);
context.AddRange(inputParameters);
context.SaveChanges();
jsonData=System.IO.File.ReadAllText(@“Data\InputParameters.json”);
var inputParameters=JsonConvert.DeserializeObject jsonData,设置);
AddRange(inputParameters);
SaveChanges();
在查看了EFCore源代码后,我提出了以下解决方案:
1。创建一个新类“SQLServerUpdateSqlGeneratorInCertidentity”,该类负责为每个插入操作打开和关闭标识插入:
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.EntityFrameworkCore.SqlServer.Update.Internal;
using Microsoft.EntityFrameworkCore.Storage;
using Microsoft.EntityFrameworkCore.Update;
/// <summary>
/// SqlServerUpdateSqlGenerator with Insert_Identity.
/// </summary>
public class SqlServerUpdateSqlGeneratorInsertIdentity : SqlServerUpdateSqlGenerator
{
/// <summary>
/// Initializes a new instance of the <see cref="SqlServerUpdateSqlGeneratorInsertIdentity"/> class.
/// </summary>
/// <param name="dependencies">The dependencies.</param>
public SqlServerUpdateSqlGeneratorInsertIdentity(UpdateSqlGeneratorDependencies dependencies)
: base(dependencies)
{
}
/// <inheritdoc/>
public override ResultSetMapping AppendBulkInsertOperation(
StringBuilder commandStringBuilder,
IReadOnlyList<ModificationCommand> modificationCommands,
int commandPosition)
{
var columns = modificationCommands[0].ColumnModifications.Where(o => o.IsWrite).Select(o => o.ColumnName)
.ToList();
var schema = modificationCommands[0].Schema;
var table = modificationCommands[0].TableName;
GenerateIdentityInsert(commandStringBuilder, table, schema, columns, on: true);
var result = base.AppendBulkInsertOperation(commandStringBuilder, modificationCommands, commandPosition);
GenerateIdentityInsert(commandStringBuilder, table, schema, columns, on: false);
return result;
}
private void GenerateIdentityInsert(
StringBuilder builder,
string table,
string schema,
IEnumerable<string> columns,
bool on)
{
var stringTypeMapping = Dependencies.TypeMappingSource.GetMapping(typeof(string));
builder.Append("IF EXISTS (SELECT * FROM [sys].[identity_columns] WHERE").Append(" [name] IN (")
.Append(string.Join(", ", columns.Select(stringTypeMapping.GenerateSqlLiteral)))
.Append(") AND [object_id] = OBJECT_ID(").Append(
stringTypeMapping.GenerateSqlLiteral(
Dependencies.SqlGenerationHelper.DelimitIdentifier(table, schema))).AppendLine("))");
builder.Append("SET IDENTITY_INSERT ")
.Append(Dependencies.SqlGenerationHelper.DelimitIdentifier(table, schema)).Append(on ? " ON" : " OFF")
.AppendLine(Dependencies.SqlGenerationHelper.StatementTerminator);
}
}
使用System.Collections.Generic;
使用System.Linq;
使用系统文本;
使用Microsoft.EntityFrameworkCore.SqlServer.Update.Internal;
使用Microsoft.EntityFrameworkCore.Storage;
使用Microsoft.EntityFrameworkCore.Update;
///
///SqlServerUpdateSqlGenerator具有Insert_标识。
///
公共类SQLServerUpdateSqlGeneratorInEntity:SqlServerUpdateSqlGenerator
{
///
///初始化类的新实例。
///
///依赖关系。
公共SqlServerUpdateSqlGeneratorInsertIdentity(UpdateSqlGeneratorDependencies依赖项)
:base(依赖项)
{
}