我对使用Dapper很感兴趣，但据我所知，它只支持查询和执行。我没有看到Dapper包含插入和更新对象的方法。
假设我们的项目(大多数项目?)需要进行插入和更新，那么与dapper一起进行插入和更新的最佳实践是什么?
我们最好不要诉诸于ADO。NET参数构建方法等。
在这一点上，我能想到的最佳答案是使用LinqToSQL进行插入和更新。还有更好的答案吗?
当前回答
使用Dapper执行CRUD操作是一项简单的任务。我已经提到了下面的示例，它们应该可以帮助您进行CRUD操作。
CRUD代码:
方法#1:当您插入来自不同实体的值时使用此方法。
using (IDbConnection db = new SqlConnection(ConfigurationManager.ConnectionStrings["myDbConnection"].ConnectionString))
{
string insertQuery = @"INSERT INTO [dbo].[Customer]([FirstName], [LastName], [State], [City], [IsActive], [CreatedOn]) VALUES (@FirstName, @LastName, @State, @City, @IsActive, @CreatedOn)";
var result = db.Execute(insertQuery, new
{
customerModel.FirstName,
customerModel.LastName,
StateModel.State,
CityModel.City,
isActive,
CreatedOn = DateTime.Now
});
}
方法#2:当您的实体属性与SQL列具有相同的名称时使用此方法。因此，Dapper作为ORM将实体属性与匹配的SQL列映射。
using (IDbConnection db = new SqlConnection(ConfigurationManager.ConnectionStrings["myDbConnection"].ConnectionString))
{
string insertQuery = @"INSERT INTO [dbo].[Customer]([FirstName], [LastName], [State], [City], [IsActive], [CreatedOn]) VALUES (@FirstName, @LastName, @State, @City, @IsActive, @CreatedOn)";
var result = db.Execute(insertQuery, customerViewModel);
}
CRUD代码:
using (IDbConnection db = new SqlConnection(ConfigurationManager.ConnectionStrings["myDbConnection"].ConnectionString))
{
string selectQuery = @"SELECT * FROM [dbo].[Customer] WHERE FirstName = @FirstName";
var result = db.Query(selectQuery, new
{
customerModel.FirstName
});
}
CRUD代码:
using (IDbConnection db = new SqlConnection(ConfigurationManager.ConnectionStrings["myDbConnection"].ConnectionString))
{
string updateQuery = @"UPDATE [dbo].[Customer] SET IsActive = @IsActive WHERE FirstName = @FirstName AND LastName = @LastName";
var result = db.Execute(updateQuery, new
{
isActive,
customerModel.FirstName,
customerModel.LastName
});
}
CRUD代码:
using (IDbConnection db = new SqlConnection(ConfigurationManager.ConnectionStrings["myDbConnection"].ConnectionString))
{
string deleteQuery = @"DELETE FROM [dbo].[Customer] WHERE FirstName = @FirstName AND LastName = @LastName";
var result = db.Execute(deleteQuery, new
{
customerModel.FirstName,
customerModel.LastName
});
}
其他回答
与其使用任何第三方库进行查询操作，我宁愿建议您自己编写查询。因为使用任何其他第三方包会带走使用dapper的主要优势，即编写查询的灵活性。
现在，为整个对象编写Insert或Update查询有一个问题。为此，你可以简单地创建如下所示的helper:
InsertQueryBuilder:
public static string InsertQueryBuilder(IEnumerable < string > fields) {
StringBuilder columns = new StringBuilder();
StringBuilder values = new StringBuilder();
foreach(string columnName in fields) {
columns.Append($ "{columnName}, ");
values.Append($ "@{columnName}, ");
}
string insertQuery = $ "({ columns.ToString().TrimEnd(',', ' ')}) VALUES ({ values.ToString().TrimEnd(',', ' ')}) ";
return insertQuery;
}
现在，通过简单地传递要插入的列的名称，整个查询将自动创建，如下所示:
List < string > columns = new List < string > {
"UserName",
"City"
}
//QueryBuilder is the class having the InsertQueryBuilder()
string insertQueryValues = QueryBuilderUtil.InsertQueryBuilder(columns);
string insertQuery = $ "INSERT INTO UserDetails {insertQueryValues} RETURNING UserId";
Guid insertedId = await _connection.ExecuteScalarAsync < Guid > (insertQuery, userObj);
您还可以通过传递TableName参数来修改该函数以返回整个INSERT语句。
确保Class属性名称与数据库中的字段名称匹配。然后只有你可以传递整个obj(如userObj在我们的情况下)和值将自动映射。
以同样的方式，你也可以有UPDATE查询的helper函数:
public static string UpdateQueryBuilder(List < string > fields) {
StringBuilder updateQueryBuilder = new StringBuilder();
foreach(string columnName in fields) {
updateQueryBuilder.AppendFormat("{0}=@{0}, ", columnName);
}
return updateQueryBuilder.ToString().TrimEnd(',', ' ');
}
像这样使用它:
List < string > columns = new List < string > {
"UserName",
"City"
}
//QueryBuilder is the class having the UpdateQueryBuilder()
string updateQueryValues = QueryBuilderUtil.UpdateQueryBuilder(columns);
string updateQuery = $"UPDATE UserDetails SET {updateQueryValues} WHERE UserId=@UserId";
await _connection.ExecuteAsync(updateQuery, userObj);
虽然在这些辅助函数中，您也需要传递您想要插入或更新的字段的名称，但至少您可以完全控制查询，并且还可以在需要时包含不同的WHERE子句。
通过这些helper函数，你将保存以下代码行:
插入查询:
$ "INSERT INTO UserDetails (UserName,City) VALUES (@UserName,@City) RETURNING UserId";
更新查询:
$"UPDATE UserDetails SET UserName=@UserName, City=@City WHERE UserId=@UserId";
这似乎是几行代码的区别，但是当涉及到对具有超过10个字段的表执行插入或更新操作时，就可以感受到区别。
您可以使用操作符的名称来传递函数中的字段名称，以避免键入错误
而不是:
List < string > columns = new List < string > {
"UserName",
"City"
}
你可以这样写:
List < string > columns = new List < string > {
nameof(UserEntity.UserName),
nameof(UserEntity.City),
}
下面是一个关于Repository Pattern的简单例子:
public interface IUserRepository
{
Task<bool> CreateUser(User user);
Task<bool> UpdateUser(User user);
}
在UserRepository中:
public class UserRepository: IUserRepository
{
private readonly IConfiguration _configuration;
public UserRepository(IConfiguration configuration)
{
_configuration = configuration;
}
public async Task<bool> CreateUser(User user)
{
using var connection = new NpgsqlConnection(_configuration.GetValue<string>("DatabaseSettings:ConnectionString"));
var affected =
await connection.ExecuteAsync
("INSERT INTO User (Name, Email, Mobile) VALUES (@Name, @Email, @Mobile)",
new { Name= user.Name, Email= user.Email, Mobile = user.Mobile});
if (affected == 0)
return false;
return true;
}
public async Task<bool> UpdateUser(User user)
{
using var connection = new NpgsqlConnection(_configuration.GetValue<string>("DatabaseSettings:ConnectionString"));
var affected = await connection.ExecuteAsync
("UPDATE User SET Name=@Name, Email= @Email, Mobile = @Mobile WHERE Id = @Id",
new { Name= user.Name, Email= user.Email, Mobile = user.Mobile , Id = user.Id });
if (affected == 0)
return false;
return true;
}
}
注意:NpgsqlConnection用于获取PostgreSQL数据库的ConnectionString
您还可以使用dapper与存储过程和通用方式，使一切易于管理。
定义你的连接:
public class Connection: IDisposable
{
private static SqlConnectionStringBuilder ConnectionString(string dbName)
{
return new SqlConnectionStringBuilder
{
ApplicationName = "Apllication Name",
DataSource = @"Your source",
IntegratedSecurity = false,
InitialCatalog = Database Name,
Password = "Your Password",
PersistSecurityInfo = false,
UserID = "User Id",
Pooling = true
};
}
protected static IDbConnection LiveConnection(string dbName)
{
var connection = OpenConnection(ConnectionString(dbName));
connection.Open();
return connection;
}
private static IDbConnection OpenConnection(DbConnectionStringBuilder connectionString)
{
return new SqlConnection(connectionString.ConnectionString);
}
protected static bool CloseConnection(IDbConnection connection)
{
if (connection.State != ConnectionState.Closed)
{
connection.Close();
// connection.Dispose();
}
return true;
}
private static void ClearPool()
{
SqlConnection.ClearAllPools();
}
public void Dispose()
{
ClearPool();
}
}
创建一个接口来定义你实际需要的Dapper方法:
public interface IDatabaseHub
{
long Execute<TModel>(string storedProcedureName, TModel model, string dbName);
/// <summary>
/// This method is used to execute the stored procedures with parameter.This is the generic version of the method.
/// </summary>
/// <param name="storedProcedureName">This is the type of POCO class that will be returned. For more info, refer to https://msdn.microsoft.com/en-us/library/vstudio/dd456872(v=vs.100).aspx. </param>
/// <typeparam name="TModel"></typeparam>
/// <param name="model">The model object containing all the values that passes as Stored Procedure's parameter.</param>
/// <returns>Returns how many rows have been affected.</returns>
Task<long> ExecuteAsync<TModel>(string storedProcedureName, TModel model, string dbName);
/// <summary>
/// This method is used to execute the stored procedures with parameter. This is the generic version of the method.
/// </summary>
/// <param name="storedProcedureName">Stored Procedure's name. Expected to be a Verbatim String, e.g. @"[Schema].[Stored-Procedure-Name]"</param>
/// <param name="parameters">Parameter required for executing Stored Procedure.</param>
/// <returns>Returns how many rows have been affected.</returns>
long Execute(string storedProcedureName, DynamicParameters parameters, string dbName);
/// <summary>
///
/// </summary>
/// <param name="storedProcedureName"></param>
/// <param name="parameters"></param>
/// <returns></returns>
Task<long> ExecuteAsync(string storedProcedureName, DynamicParameters parameters, string dbName);
}
实现接口:
public class DatabaseHub : Connection, IDatabaseHub
{
/// <summary>
/// This function is used for validating if the Stored Procedure's name is correct.
/// </summary>
/// <param name="storedProcedureName">Stored Procedure's name. Expected to be a Verbatim String, e.g. @"[Schema].[Stored-Procedure-Name]"</param>
/// <returns>Returns true if name is not empty and matches naming patter, otherwise returns false.</returns>
private static bool IsStoredProcedureNameCorrect(string storedProcedureName)
{
if (string.IsNullOrEmpty(storedProcedureName))
{
return false;
}
if (storedProcedureName.StartsWith("[") && storedProcedureName.EndsWith("]"))
{
return Regex.IsMatch(storedProcedureName,
@"^[\[]{1}[A-Za-z0-9_]+[\]]{1}[\.]{1}[\[]{1}[A-Za-z0-9_]+[\]]{1}$");
}
return Regex.IsMatch(storedProcedureName, @"^[A-Za-z0-9]+[\.]{1}[A-Za-z0-9]+$");
}
/// <summary>
/// This method is used to execute the stored procedures without parameter.
/// </summary>
/// <param name="storedProcedureName">Stored Procedure's name. Expected to be a Verbatim String, e.g. @"[Schema].[Stored-Procedure-Name]"</param>
/// <param name="model">The model object containing all the values that passes as Stored Procedure's parameter.</param>
/// <typeparam name="TModel">This is the type of POCO class that will be returned. For more info, refer to https://msdn.microsoft.com/en-us/library/vstudio/dd456872(v=vs.100).aspx. </typeparam>
/// <returns>Returns how many rows have been affected.</returns>
public long Execute<TModel>(string storedProcedureName, TModel model, string dbName)
{
if (!IsStoredProcedureNameCorrect(storedProcedureName))
{
return 0;
}
using (var connection = LiveConnection(dbName))
{
try
{
return connection.Execute(
sql: storedProcedureName,
param: model,
commandTimeout: null,
commandType: CommandType.StoredProcedure
);
}
catch (Exception exception)
{
throw exception;
}
finally
{
CloseConnection(connection);
}
}
}
public async Task<long> ExecuteAsync<TModel>(string storedProcedureName, TModel model, string dbName)
{
if (!IsStoredProcedureNameCorrect(storedProcedureName))
{
return 0;
}
using (var connection = LiveConnection(dbName))
{
try
{
return await connection.ExecuteAsync(
sql: storedProcedureName,
param: model,
commandTimeout: null,
commandType: CommandType.StoredProcedure
);
}
catch (Exception exception)
{
throw exception;
}
finally
{
CloseConnection(connection);
}
}
}
/// <summary>
/// This method is used to execute the stored procedures with parameter. This is the generic version of the method.
/// </summary>
/// <param name="storedProcedureName">Stored Procedure's name. Expected to be a Verbatim String, e.g. @"[Schema].[Stored-Procedure-Name]"</param>
/// <param name="parameters">Parameter required for executing Stored Procedure.</param>
/// <returns>Returns how many rows have been affected.</returns>
public long Execute(string storedProcedureName, DynamicParameters parameters, string dbName)
{
if (!IsStoredProcedureNameCorrect(storedProcedureName))
{
return 0;
}
using (var connection = LiveConnection(dbName))
{
try
{
return connection.Execute(
sql: storedProcedureName,
param: parameters,
commandTimeout: null,
commandType: CommandType.StoredProcedure
);
}
catch (Exception exception)
{
throw exception;
}
finally
{
CloseConnection(connection);
}
}
}
public async Task<long> ExecuteAsync(string storedProcedureName, DynamicParameters parameters, string dbName)
{
if (!IsStoredProcedureNameCorrect(storedProcedureName))
{
return 0;
}
using (var connection = LiveConnection(dbName))
{
try
{
return await connection.ExecuteAsync(
sql: storedProcedureName,
param: parameters,
commandTimeout: null,
commandType: CommandType.StoredProcedure
);
}
catch (Exception exception)
{
throw exception;
}
finally
{
CloseConnection(connection);
}
}
}
}
你现在可以从模型调用你的需要:
public class DeviceDriverModel : Base
{
public class DeviceDriverSaveUpdate
{
public string DeviceVehicleId { get; set; }
public string DeviceId { get; set; }
public string DriverId { get; set; }
public string PhoneNo { get; set; }
public bool IsActive { get; set; }
public string UserId { get; set; }
public string HostIP { get; set; }
}
public Task<long> DeviceDriver_SaveUpdate(DeviceDriverSaveUpdate obj)
{
return DatabaseHub.ExecuteAsync(
storedProcedureName: "[dbo].[sp_SaveUpdate_DeviceDriver]", model: obj, dbName: AMSDB);//Database name defined in Base Class.
}
}
你也可以传递参数:
public Task<long> DeleteFuelPriceEntryByID(string FuelPriceId, string UserId)
{
var parameters = new DynamicParameters();
parameters.Add(name: "@FuelPriceId", value: FuelPriceId, dbType: DbType.Int32, direction: ParameterDirection.Input);
parameters.Add(name: "@UserId", value: UserId, dbType: DbType.String, direction: ParameterDirection.Input);
return DatabaseHub.ExecuteAsync(
storedProcedureName: @"[dbo].[sp_Delete_FuelPriceEntryByID]", parameters: parameters, dbName: AMSDB);
}
现在从你的控制器调用:
var queryData = new DeviceDriverModel().DeviceInfo_Save(obj);
希望它能防止代码重复，并提供安全性;
使用Dapper执行CRUD操作是一项简单的任务。我已经提到了下面的示例，它们应该可以帮助您进行CRUD操作。
CRUD代码:
方法#1:当您插入来自不同实体的值时使用此方法。
using (IDbConnection db = new SqlConnection(ConfigurationManager.ConnectionStrings["myDbConnection"].ConnectionString))
{
string insertQuery = @"INSERT INTO [dbo].[Customer]([FirstName], [LastName], [State], [City], [IsActive], [CreatedOn]) VALUES (@FirstName, @LastName, @State, @City, @IsActive, @CreatedOn)";
var result = db.Execute(insertQuery, new
{
customerModel.FirstName,
customerModel.LastName,
StateModel.State,
CityModel.City,
isActive,
CreatedOn = DateTime.Now
});
}
方法#2:当您的实体属性与SQL列具有相同的名称时使用此方法。因此，Dapper作为ORM将实体属性与匹配的SQL列映射。
using (IDbConnection db = new SqlConnection(ConfigurationManager.ConnectionStrings["myDbConnection"].ConnectionString))
{
string insertQuery = @"INSERT INTO [dbo].[Customer]([FirstName], [LastName], [State], [City], [IsActive], [CreatedOn]) VALUES (@FirstName, @LastName, @State, @City, @IsActive, @CreatedOn)";
var result = db.Execute(insertQuery, customerViewModel);
}
CRUD代码:
using (IDbConnection db = new SqlConnection(ConfigurationManager.ConnectionStrings["myDbConnection"].ConnectionString))
{
string selectQuery = @"SELECT * FROM [dbo].[Customer] WHERE FirstName = @FirstName";
var result = db.Query(selectQuery, new
{
customerModel.FirstName
});
}
CRUD代码:
using (IDbConnection db = new SqlConnection(ConfigurationManager.ConnectionStrings["myDbConnection"].ConnectionString))
{
string updateQuery = @"UPDATE [dbo].[Customer] SET IsActive = @IsActive WHERE FirstName = @FirstName AND LastName = @LastName";
var result = db.Execute(updateQuery, new
{
isActive,
customerModel.FirstName,
customerModel.LastName
});
}
CRUD代码:
using (IDbConnection db = new SqlConnection(ConfigurationManager.ConnectionStrings["myDbConnection"].ConnectionString))
{
string deleteQuery = @"DELETE FROM [dbo].[Customer] WHERE FirstName = @FirstName AND LastName = @LastName";
var result = db.Execute(deleteQuery, new
{
customerModel.FirstName,
customerModel.LastName
});
}
你可以这样做:
sqlConnection.Open();
string sqlQuery = "INSERT INTO [dbo].[Customer]([FirstName],[LastName],[Address],[City]) VALUES (@FirstName,@LastName,@Address,@City)";
sqlConnection.Execute(sqlQuery,
new
{
customerEntity.FirstName,
customerEntity.LastName,
customerEntity.Address,
customerEntity.City
});
Caius补充的编辑:
注意，没有必要以这种“操作之前/之后立即”的方式打开/关闭连接:如果您的连接关闭了，Dapper会打开它。如果你的连接是开放的，Dapper会让它保持开放。
如果你有很多操作要执行/你正在使用一个事务，你可以自己打开连接。如果你要做的只是打开/执行/关闭，就让Dapper来做。
而且，没有必要创建匿名类型;只要使参数名称与保存数据的任何类型的属性名称相匹配，并传递该类型而不是将其解压缩为匿名类型。
上面的代码可以这样写:
string sqlQuery = "INSERT INTO [dbo].[Customer]([FirstName],[LastName],[Address],[City]) VALUES (@FirstName,@LastName,@Address,@City)";
using(var sqlConnection = ...){
sqlConnection.Execute(sqlQuery, customerEntity);
}
