Entity Framework Core，执行原始 SQL 并参数化表名

Question

I am using Entity Framework Core and when I run the following query it all works as expected and selects all entities from the flasher_equipment table.

public async Task<IEnumerable<BaseEquipmentType>> GetNewAvailableEquipment(string tableName)
{
    DbSet<BaseEquipmentType> dbSet = _context.Set<BaseEquipmentType>();
    IQueryable<BaseEquipmentType> types = dbSet.FromSql($"select * from flasher_equipment");
    return await types.ToArrayAsync();
}

but now, instead of hard coding the table name ( flasher_equipment ) I want to pass it as a parameter.

I've tried changing the code as follows:

public async Task<IEnumerable<BaseEquipmentType>> GetNewAvailableEquipment(string tableName)
{
    DbSet<BaseEquipmentType> dbSet = _context.Set<BaseEquipmentType>();
    IQueryable<BaseEquipmentType> types = dbSet.FromSql($"select * from {tableName}");
    return await types.ToArrayAsync();
}

and I've also tried

public async Task<IEnumerable<BaseEquipmentType>> GetNewAvailableEquipment(string tableName)
{
    DbSet<BaseEquipmentType> dbSet = _context.Set<BaseEquipmentType>();
    IQueryable<BaseEquipmentType> types = dbSet.FromSql("select * from {0}", tableName);
    return await types.ToArrayAsync();
}

Each time I get an error:

Grpc.AspNetCore.Server.ServerCallHandler[6]
Error when executing service method 'GetByPlanIdAnImplementation'. Oracle.ManagedDataAccess.Client.OracleException (0x80004005): ORA-00903: invalid table name

Why is parameterizing the table name as a parameter causing it to crash?

Answer 1

Seems to be an problem of the FromSql method with the string interpolation .

Probably it will work if you interpolate the string outside the method, as:

public async Task<IEnumerable<BaseEquipmentType>> GetNewAvailableEquipment(string tableName)
{
    DbSet<BaseEquipmentType> dbSet = _context.Set<BaseEquipmentType>();
    string sqlStatement = $"select * from {tableName}"; 
    IQueryable<BaseEquipmentType> types = dbSet.FromSql(sqlStatement);
    return await types.ToArrayAsync();
}