publicstaticIEnumerable<dynamic> Query (thisIDbConnection cnn,stringsql,objectparam =null, SqlTransaction transaction =null,boolbuffered =true) 该方法将执行 SQL,并返回一个动态 list,即var变量。 用法: var rows = connection.Query("select 1 A, 2 B union all select 3, 4"); ((int)rows[0].A)...
Dapper is, therefore, a good choice in scenarios where read-only data changes frequently and is requested often. It is particularly good in stateless scenarios (e.g. the web) where there is no need to persist complex object graphs in memory for any duration. Dapper does not translate querie...
Complexity Dapper is very simple to use, you just have to execute the query to the database. EF Core is a little complex since there is a higher-level, object-oriented approach to database operations. You have to be good at LINQ. Learning Curve Dapper has a low learning curve. All it...
res = connection.Query(sql, dynParms).FirstOrDefault() as IDictionary<string, object>; if (res == null) return (T)((object)null); obj = ProxyGenerator.GetInterfaceProxy<T>(); foreach (var property in TypePropertiesCache(type)) { var val = res[property.Name]; property.SetValue(obj, ...
QuerySingleAsync<SalesOrder>(sql, param) .ConfigureAwait(false); }Note the query must return exactly a single row. If not, Dapper unwinds the call stack via a thrown exception. This guarantees one object in the return type, so the compiler can assume this is not nullable....
All the Query APIs will always return an object per database row. So, this works well on the many -> one direction, but less well for the one -> many multi-map. There are 2 issues here: If we introduce a built-in mapper that works with your query, we would be expected to "...
Performance: While both approaches are performant, Dapper's lightweight nature often leads to faster execution times, especially in scenarios involving complex object mapping. Readability and Maintainability: Dapper's use of object mapping can lead to cleaner and more concise code, making it easier to...
You tell dapper that the query returns a Post and a User object and then give it a function describing what you want to do with each of the rows containing both a Post and a User object. In our case, we want to take the user object and put it inside the post object. So we ...
QueryBuilder($@" SELECT ProductId, Name, ListPrice, Weight FROM Product WHERE Price>{minPrice} /**filters**/ ORDER BY ProductId "); When Dapper is invoked we replace the /**filters**/ by AND <filter1> AND <filter2...> (if any filter was added). Writing complex filters (combining...
public static IEnumerable<T> Query<T>(this IDbConnection cnn, string sql, object param = null, SqlTransaction transaction = null, bool buffered = true) Example usage: public class Dog { public int? Age { get; set; } public Guid Id { get; set; } public string Name { get; set; }...