.Net linq2db，FluentMappingBuilder，表名不适用于查询

Question

我正在深入研究 linq2db 的一个小项目。我已经设置了模型、连接和简单的查询。但事情是这样的：每次运行查询时，linq2db 都会使用实体模型中的表名称，而不是 fluencemapper 中的名称。我是否遗漏了有关使用 MappingSchema() 和 FlumentMappingBuilder 的信息？帮助 linq2db 的新手吗？ 🤔 我使用 sqlite 数据库...

public class SparkleContext : DataConnection
    {
        public SparkleContext(DataOptions<SparkleContext> options)
            : base(options.Options)
        {
            AddMappingSchema(new SparkleMappingSchema());
        }

        public ITable<CompanyEm> Companies => this.GetTable<CompanyEm>();

        public ITable<MeterEm> Meters => this.GetTable<MeterEm>();

        public ITable<ReadingsEm> Readings => this.GetTable<ReadingsEm>();
    }

和映射模式

   public class SparkleMappingSchema : MappingSchema
    {
        public SparkleMappingSchema()
        {
            var mappings = new MappingSchema();

            var builder = new FluentMappingBuilder(mappings);

            builder.Entity<CompanyEm>().HasTableName("Companies")
                .Property(x => x.Id).HasColumnName("Id").IsIdentity().IsPrimaryKey()
                .Property(x => x.Name).HasColumnName("Name").IsNotNull()
                .Property(x => x.Description).HasColumnName("Description").IsNullable()
                .Property(x => x.Meters).HasColumnName("Meters").IsNullable()
                .Property(x => x.CreatedAt).HasColumnName("CreatedAt").IsNullable()
                .Property(x => x.UpdatedAt).HasColumnName("UpdatedAt").IsNullable();

            builder.Entity<MeterEm>().HasTableName("Meters")
                .Property(x => x.Id).HasColumnName("Id").IsIdentity().IsPrimaryKey()
                .Property(x => x.Name).HasColumnName("Name").IsNotNull()
                .Property(x => x.Readings).HasColumnName("Readings").IsNullable()
                .Property(x => x.CreatedAt).HasColumnName("CreatedAt").IsNullable()
                .Property(x => x.UpdatedAt).HasColumnName("UpdatedAt").IsNullable();

            builder.Entity<ReadingsEm>().HasTableName("Readings")
                .Property(x => x.Id).HasColumnName("Id").IsIdentity().IsPrimaryKey()
                .Property(x => x.Time).HasColumnName("Time").IsNotNull()
                .Property(x => x.Value).HasColumnName("Value").IsNotNull()
                .Property(x => x.CreatedAt).HasColumnName("CreatedAt").IsNullable()
                .Property(x => x.UpdatedAt).HasColumnName("UpdatedAt").IsNullable();
        }
    }

和小查询

 using var sparkleDb = new DataConnection(context.DataProvider, context.ConnectionString);

            var test = context.Companies.Where(x => x.Name == "God_Company").Select(x => x.Id).AsQueryable();

错误是这样的 System.Data.SQLite.SQLiteException: 'SQL 逻辑错误 没有这样的表：CompanyEm'

Answer 1

这是因为你定义了错误的映射

MappingSchema

。使用

FluentMappingBuilder

参数创建

this

。

public class SparkleMappingSchema: MappingSchema
{
    public SparkleMappingSchema()
    {
        var builder = new FluentMappingBuilder(this);

        builder.Entity<CompanyEm>().HasTableName("Companies")
            .Property(x => x.Id).HasColumnName("Id").IsIdentity().IsPrimaryKey()
            .Property(x => x.Name).HasColumnName("Name").IsNotNull()
            .Property(x => x.Description).HasColumnName("Description").IsNullable()
            .Property(x => x.Meters).HasColumnName("Meters").IsNullable()
            .Property(x => x.CreatedAt).HasColumnName("CreatedAt").IsNullable()
            .Property(x => x.UpdatedAt).HasColumnName("UpdatedAt").IsNullable();

        .....

        builder.Build();
    }
}