我想先使用dotnet ef migrations add Seed（成功）然后使用dotnet ef update database（失败）为我的Products表添加一些初始数据。
dotnet ef update database输出：
...
fail: Microsoft.EntityFrameworkCore.Database.Command[20102]
Failed executing DbCommand (139ms) [Parameters=[], CommandType='Text', CommandTimeout='30']
INSERT INTO `Products` (`Id`, `CategoryId`, `Name`, `QuantityInPackage`, `UnitOfMeasurement`)
VALUES (100, 100, 'Apple', 1, 1);
MySql.Data.MySqlClient.MySqlException (0x80004005): Cannot add or update a child row: a foreign key constraint fails (`SupermarketDB`.`Products`, CONSTRAINT `FK_Products_Categories_CategoryId` FOREIGN KEY (`CategoryId`) REFERENCES `Categories` (`Id`) ON DELETE CASCADE) ---> MySql.Data.MySqlClient.MySqlException (0x80004005): Cannot add or update a child row: a foreign key constraint fails (`SupermarketDB`.`Products`, CONSTRAINT `FK_Products_Categories_CategoryId` FOREIGN KEY (`CategoryId`) REFERENCES `Categories` (`Id`) ON DELETE CASCADE)
.
.
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Cannot add or update a child row: a foreign key constraint fails (`SupermarketDB`.`Products`, CONSTRAINT `FK_Products_Categories_CategoryId` FOREIGN KEY (`CategoryId`) REFERENCES `Categories` (`Id`) ON DELETE CASCADE)
根据我的理解，它基本上是说我想将数据与不存在的不正确数据相关联。 然后，我尝试通过从错误消息中复制粘贴查询，通过mysql cli直接将其插入，这样就可以了。
为什么我无法通过dotnet ef ...实现这一目标？如何正确执行？
$ dotnet --version
2.2.202
$ dotnet ef --version
Entity Framework Core .NET Command-line Tools
2.2.3-servicing-35854
表格“类别”
+-------+-------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+----------------+
| Id | int(11) | NO | PRI | NULL | auto_increment |
| Name | varchar(30) | NO | | NULL | |
+-------+-------------+------+-----+---------+----------------+
+-----+--------------------+
| Id | Name |
+-----+--------------------+
| 100 | Fruits and Veggies |
| 101 | Dairy |
| 102 | Bakery |
| 104 | Sweets |
+-----+--------------------+
表“产品”
+-------------------+---------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-------------------+---------------------+------+-----+---------+----------------+
| Id | int(11) | NO | PRI | NULL | auto_increment |
| Name | varchar(50) | NO | | NULL | |
| QuantityInPackage | smallint(6) | NO | | NULL | |
| UnitOfMeasurement | tinyint(3) unsigned | NO | | NULL | |
| CategoryId | int(11) | NO | MUL | NULL | |
+-------------------+---------------------+------+-----+---------+----------------+
empty
AppDbContext.cs
protected override void OnModelCreating(ModelBuilder builder)
{
base.OnModelCreating(builder);
builder.Entity<Category>().ToTable("Categories");
builder.Entity<Category>().HasKey(p => p.Id);
builder.Entity<Category>().Property(p => p.Id).IsRequired().ValueGeneratedOnAdd();
builder.Entity<Category>().Property(p => p.Name).IsRequired().HasMaxLength(30);
builder.Entity<Category>().HasMany(p => p.Products).WithOne(p => p.Category).HasForeignKey(p => p.CategoryId);
builder.Entity<Category>().HasData(
new Category { Id = 100, Name = "Fruits and Veggies" },
new Category { Id = 101, Name = "Dairy" }
);
builder.Entity<Product>().ToTable("Products");
builder.Entity<Product>().HasKey(p => p.Id);
builder.Entity<Product>().Property(p => p.Id).IsRequired().ValueGeneratedOnAdd();
builder.Entity<Product>().Property(p => p.Name).IsRequired().HasMaxLength(50);
builder.Entity<Product>().Property(p => p.QuantityInPackage).IsRequired();
builder.Entity<Product>().Property(p => p.UnitOfMeasurement).IsRequired();
builder.Entity<Product>().HasData(
new Product {
Id = 100,
Name = "Apple",
QuantityInPackage = 1,
UnitOfMeasurement = EUnitOfMeasurement.Unity,
CategoryId = 100
},
new Product {
Id = 101,
Name = "Emmental Cheese",
QuantityInPackage = 150,
UnitOfMeasurement = EUnitOfMeasurement.Gram,
CategoryId = 101
}
);
}
完成dotnet ef update database输出：
info: Microsoft.EntityFrameworkCore.Infrastructure[10403]
Entity Framework Core 2.2.4-servicing-10062 initialized 'AppDbContext' using provider 'Pomelo.EntityFrameworkCore.MySql' with options: None
info: Microsoft.EntityFrameworkCore.Database.Command[20101]
Executed DbCommand (68ms) [Parameters=[], CommandType='Text', CommandTimeout='30']
SELECT 1 FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA='SupermarketDB' AND TABLE_NAME='__EFMigrationsHistory';
info: Microsoft.EntityFrameworkCore.Database.Command[20101]
Executed DbCommand (1ms) [Parameters=[], CommandType='Text', CommandTimeout='30']
SELECT 1 FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA='SupermarketDB' AND TABLE_NAME='__EFMigrationsHistory';
info: Microsoft.EntityFrameworkCore.Database.Command[20101]
Executed DbCommand (3ms) [Parameters=[], CommandType='Text', CommandTimeout='30']
SELECT `MigrationId`, `ProductVersion`
FROM `__EFMigrationsHistory`
ORDER BY `MigrationId`;
info: Microsoft.EntityFrameworkCore.Migrations[20402]
Applying migration '20190604143215_AddSeeds'.
Applying migration '20190604143215_AddSeeds'.
info: Microsoft.EntityFrameworkCore.Database.Command[20101]
Executed DbCommand (2ms) [Parameters=[], CommandType='Text', CommandTimeout='30']
DELETE FROM `Categories`
WHERE `Id` = 100;
SELECT ROW_COUNT();
info: Microsoft.EntityFrameworkCore.Database.Command[20101]
Executed DbCommand (2ms) [Parameters=[], CommandType='Text', CommandTimeout='30']
DELETE FROM `Categories`
WHERE `Id` = 101;
SELECT ROW_COUNT();
fail: Microsoft.EntityFrameworkCore.Database.Command[20102]
Failed executing DbCommand (139ms) [Parameters=[], CommandType='Text', CommandTimeout='30']
INSERT INTO `Products` (`Id`, `CategoryId`, `Name`, `QuantityInPackage`, `UnitOfMeasurement`)
VALUES (100, 100, 'Apple', 1, 1);
MySql.Data.MySqlClient.MySqlException (0x80004005): Cannot add or update a child row: a foreign key constraint fails (`SupermarketDB`.`Products`, CONSTRAINT `FK_Products_Categories_CategoryId` FOREIGN KEY (`CategoryId`) REFERENCES `Categories` (`Id`) ON DELETE CASCADE) ---> MySql.Data.MySqlClient.MySqlException (0x80004005): Cannot add or update a child row: a foreign key constraint fails (`SupermarketDB`.`Products`, CONSTRAINT `FK_Products_Categories_CategoryId` FOREIGN KEY (`CategoryId`) REFERENCES `Categories` (`Id`) ON DELETE CASCADE)
at MySqlConnector.Core.ResultSet.ReadResultSetHeaderAsync(IOBehavior ioBehavior) in C:\projects\mysqlconnector\src\MySqlConnector\Core\ResultSet.cs:line 43
at MySql.Data.MySqlClient.MySqlDataReader.ActivateResultSet(ResultSet resultSet) in C:\projects\mysqlconnector\src\MySqlConnector\MySql.Data.MySqlClient\MySqlDataReader.cs:line 81
at MySql.Data.MySqlClient.MySqlDataReader.ReadFirstResultSetAsync(IOBehavior ioBehavior) in C:\projects\mysqlconnector\src\MySqlConnector\MySql.Data.MySqlClient\MySqlDataReader.cs:line 307
at MySql.Data.MySqlClient.MySqlDataReader.CreateAsync(MySqlCommand command, CommandBehavior behavior, ResultSetProtocol resultSetProtocol, IOBehavior ioBehavior) in C:\projects\mysqlconnector\src\MySqlConnector\MySql.Data.MySqlClient\MySqlDataReader.cs:line 292
at MySqlConnector.Core.TextCommandExecutor.ExecuteReaderAsync(String commandText, MySqlParameterCollection parameterCollection, CommandBehavior behavior, IOBehavior ioBehavior, CancellationToken cancellationToken) in C:\projects\mysqlconnector\src\MySqlConnector\Core\TextCommandExecutor.cs:line 37
at MySql.Data.MySqlClient.MySqlCommand.ExecuteNonQueryAsync(IOBehavior ioBehavior, CancellationToken cancellationToken) in C:\projects\mysqlconnector\src\MySqlConnector\MySql.Data.MySqlClient\MySqlCommand.cs:line 276
at MySql.Data.MySqlClient.MySqlCommand.ExecuteNonQuery() in C:\projects\mysqlconnector\src\MySqlConnector\MySql.Data.MySqlClient\MySqlCommand.cs:line 77
at Microsoft.EntityFrameworkCore.Storage.Internal.RelationalCommand.Execute(IRelationalConnection connection, DbCommandMethod executeMethod, IReadOnlyDictionary`2 parameterValues)
Failed executing DbCommand (139ms) [Parameters=[], CommandType='Text', CommandTimeout='30']
INSERT INTO `Products` (`Id`, `CategoryId`, `Name`, `QuantityInPackage`, `UnitOfMeasurement`)
VALUES (100, 100, 'Apple', 1, 1);
MySql.Data.MySqlClient.MySqlException (0x80004005): Cannot add or update a child row: a foreign key constraint fails (`SupermarketDB`.`Products`, CONSTRAINT `FK_Products_Categories_CategoryId` FOREIGN KEY (`CategoryId`) REFERENCES `Categories` (`Id`) ON DELETE CASCADE) ---> MySql.Data.MySqlClient.MySqlException (0x80004005): Cannot add or update a child row: a foreign key constraint fails (`SupermarketDB`.`Products`, CONSTRAINT `FK_Products_Categories_CategoryId` FOREIGN KEY (`CategoryId`) REFERENCES `Categories` (`Id`) ON DELETE CASCADE)
at MySqlConnector.Core.ResultSet.ReadResultSetHeaderAsync(IOBehavior ioBehavior) in C:\projects\mysqlconnector\src\MySqlConnector\Core\ResultSet.cs:line 43
at MySql.Data.MySqlClient.MySqlDataReader.ActivateResultSet(ResultSet resultSet) in C:\projects\mysqlconnector\src\MySqlConnector\MySql.Data.MySqlClient\MySqlDataReader.cs:line 81
at MySql.Data.MySqlClient.MySqlDataReader.ReadFirstResultSetAsync(IOBehavior ioBehavior) in C:\projects\mysqlconnector\src\MySqlConnector\MySql.Data.MySqlClient\MySqlDataReader.cs:line 307
at MySql.Data.MySqlClient.MySqlDataReader.CreateAsync(MySqlCommand command, CommandBehavior behavior, ResultSetProtocol resultSetProtocol, IOBehavior ioBehavior) in C:\projects\mysqlconnector\src\MySqlConnector\MySql.Data.MySqlClient\MySqlDataReader.cs:line 292
at MySqlConnector.Core.TextCommandExecutor.ExecuteReaderAsync(String commandText, MySqlParameterCollection parameterCollection, CommandBehavior behavior, IOBehavior ioBehavior, CancellationToken cancellationToken) in C:\projects\mysqlconnector\src\MySqlConnector\Core\TextCommandExecutor.cs:line 37
at MySql.Data.MySqlClient.MySqlCommand.ExecuteNonQueryAsync(IOBehavior ioBehavior, CancellationToken cancellationToken) in C:\projects\mysqlconnector\src\MySqlConnector\MySql.Data.MySqlClient\MySqlCommand.cs:line 276
at MySql.Data.MySqlClient.MySqlCommand.ExecuteNonQuery() in C:\projects\mysqlconnector\src\MySqlConnector\MySql.Data.MySqlClient\MySqlCommand.cs:line 77
at Microsoft.EntityFrameworkCore.Storage.Internal.RelationalCommand.Execute(IRelationalConnection connection, DbCommandMethod executeMethod, IReadOnlyDictionary`2 parameterValues)
at Microsoft.EntityFrameworkCore.Storage.Internal.RelationalCommand.ExecuteNonQuery(IRelationalConnection connection, IReadOnlyDictionary`2 parameterValues)
at Microsoft.EntityFrameworkCore.Migrations.MigrationCommand.ExecuteNonQuery(IRelationalConnection connection, IReadOnlyDictionary`2 parameterValues)
at Microsoft.EntityFrameworkCore.Migrations.Internal.MigrationCommandExecutor.ExecuteNonQuery(IEnumerable`1 migrationCommands, IRelationalConnection connection)
at Microsoft.EntityFrameworkCore.Migrations.Internal.Migrator.Migrate(String targetMigration)
at Microsoft.EntityFrameworkCore.Design.Internal.MigrationsOperations.UpdateDatabase(String targetMigration, String contextType)
at Microsoft.EntityFrameworkCore.Design.OperationExecutor.UpdateDatabase.<>c__DisplayClass0_1.<.ctor>b__0()
at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.Execute(Action action)
Cannot add or update a child row: a foreign key constraint fails (`SupermarketDB`.`Products`, CONSTRAINT `FK_Products_Categories_CategoryId` FOREIGN KEY (`CategoryId`) REFERENCES `Categories` (`Id`) ON DELETE CASCADE)