i wonder how to implement M-V-C ADO without using EF.
just like a pure ADO implementation. any suggestions and sample are appreciated Thanks guys.
Basic ADO.NET connections haven't really changed at all with MVC coming around. They still rely on things like SqlConnection objects and their associated commands.
If you wanted to build a simply query, it might look like the following :
// Build your connection
using(var connection = new SqlConnection("{your-connection-string-here"}))
{
// Build your query
var query = "SELECT * FROM YourTable WHERE foo = #bar";
// Create a command to execute your query
using(var command = new SqlCommand(query,connection))
{
// Open the connection
connection.Open();
// Add any parameters if necessary
command.Parameters.AddWithValue("#bar", 42);
// Execute your query here (in this case using a data reader)
using(var reader = command.ExecuteReader())
{
// Iterate through your results
while(reader.Read())
{
// The current reader object will contain each row here, so you
// can access the values as expected
}
}
}
}
You can use the type of ADO commands and paramaterized SQL seen here to retrieve data:
conn.Open();
cmd.CommandText = "SELECT id, desc FROM mytable WHERE id = #id";
cmd.Parameters.AddWithValue("#id", myid);
using (var reader = cmd.ExecuteReader())
{
if (!reader.Read())
{
return null;
}
return new myItem
{
Id = reader.GetInt32(reader.GetOrdinal("id")),
Desc = reader.GetString(reader.GetOrdinal("desc")),
}
}
There are lot of examples on MSDN for CRUD.
Related
I use NReco.Data in my Asp.NetCore Application to make db-calls, because I don't want to use EF and DataTable isn't supported yet.
Now I need to call a StoredProcedure and get Multiple RecordSets (or Dictionarylists).
At the moment I called this:
dbAdapter.Select($"STOREDNAME #{nameof(SQLPARAMETER)}", SQLPARAMETER).ToRecordSet()
But the stored gives me more than 1 recordset, can anyone help me to get the others?
Currently NReco.Data.DbDataAdapter has no API for processing multiple result sets returned by single IDbCommand.
You can compose IDbCommand by yourself, execute data reader and read multiple result sets in the following way:
IDbCommand spCmd; // lets assume that this is DB command for 'STOREDNAME'
RecordSet rs1 = null;
RecordSet rs2 = null;
spCmd.Connection.Open();
try {
using (var rdr = spCmd.ExecuteReader()) {
rs1 = RecordSet.FromReader(rdr);
if (rdr.NextResult())
rs2 = RecordSet.FromReader(rdr);
}
} finally {
spCmd.Connection.Close();
}
As NReco.Data author I think that support for multiple result sets may be easily added to DbDataAdapter API (I've just created an issue for that on github).
-- UPDATE --
Starting from NReco.Data v.1.0.2 it is possible to handle multiple result sets in the following way:
(var companies, var contacts) = DbAdapter.Select("exec STOREDNAME").ExecuteReader(
(rdr) => {
var companiesRes = new DataReaderResult(rdr).ToList<CompanyModel>();
rdr.NextResult();
var contactsRes = new DataReaderResult(rdr).ToList<ContactModel>();
return (companiesRes, contactsRes);
});
In the same manner DataReaderResult can map results to dictionaries or RecordSet if needed.
I have ASP.Net MVC 5 Web API project.
I cant use asp.net web API 2 web service in android
my web service is under mvc5, Then I have created mobile app in Eclipse Juno and i use Android sdk 21
below is my edited code
namespace AppServices.Models
{
public class AdvertisingRepository
{
private List<Advertising> Advertising = new List<Advertising>();
private int _nextId = 1;
public AdvertisingRepository()
{
}
public List<Advertising> GetAll()
{
Advertising.Clear();
SqlDataReader reader = null;
SqlConnection myConnection = new SqlConnection();
myConnection.ConnectionString = #"Server=.;Database=AppServices;User ID=sa;Password=123;";
SqlCommand sqlCmd = new SqlCommand();
sqlCmd.CommandType = CommandType.Text;
sqlCmd.CommandText = "SELECT * FROM tblAdvertising";
sqlCmd.Connection = myConnection;
myConnection.Open();
reader = sqlCmd.ExecuteReader();
Advertising emp = null;
while (reader.Read())
{
emp = new Advertising();
emp.Id = Convert.ToInt32(reader.GetValue(0));
emp.SearchString = reader.GetValue(1).ToString();
emp.OstanID = Convert.ToInt32(reader.GetValue(2));
emp.AdsGroupID = Convert.ToInt32(reader.GetValue(3));
Advertising.Add(emp);
}
myConnection.Close();
return Advertising;
}
public Advertising Get(int id)
{
Advertising.Clear();
SqlDataReader reader = null;
SqlConnection myConnection = new SqlConnection();
myConnection.ConnectionString = #"Server=.;Database=AppServices;User ID=sa;Password=123;";
SqlCommand sqlCmd = new SqlCommand();
sqlCmd.CommandType = CommandType.Text;
sqlCmd.CommandText = "SELECT * FROM tblAdvertising WHERE Id=" + id + "";
sqlCmd.Connection = myConnection;
myConnection.Open();
reader = sqlCmd.ExecuteReader();
Advertising emp = null;
while (reader.Read())
{
emp = new Advertising();
emp.Id = Convert.ToInt32(reader.GetValue(0));
emp.SearchString = reader.GetValue(1).ToString();
emp.OstanID = Convert.ToInt32(reader.GetValue(2));
emp.AdsGroupID = Convert.ToInt32(reader.GetValue(3));
Advertising.Add(emp);
}
myConnection.Close();
return Advertising.Find(p => p.Id == id);
}
public Advertising Add(Advertising item)
{
SqlConnection myConnection = new SqlConnection();
myConnection.ConnectionString = #"Server=.;Database=AppServices;User ID=sa;Password=123;";
SqlCommand sqlCmd = new SqlCommand();
sqlCmd.CommandType = CommandType.Text;
sqlCmd.CommandText = "INSERT INTO tblAdvertising (SearchString, OstanID, AdsGroupID) VALUES (#SearchString, #OstanID, #AdsGroupID)";
sqlCmd.Connection = myConnection;
sqlCmd.Parameters.AddWithValue("#SearchString", item.SearchString);
sqlCmd.Parameters.AddWithValue("#OstanID", item.OstanID);
sqlCmd.Parameters.AddWithValue("#AdsGroupID", item.AdsGroupID);
myConnection.Open();
int rowInserted = sqlCmd.ExecuteNonQuery();
// Get new record id
sqlCmd.CommandText = "SELECT TOP (1) Id FROM tblAdvertising ORDER BY Id DESC";
if (sqlCmd.ExecuteScalar() != DBNull.Value)
_nextId = (int)sqlCmd.ExecuteScalar();
////////////////////
myConnection.Close();
// old code
if (item == null)
{
throw new ArgumentNullException("item");
}
item.Id = _nextId;
Advertising.Add(item);
return item;
}
public void Remove(int id)
{
Advertising.RemoveAll(p => p.Id == id);
}
public bool Update(Advertising item)
{
if (item == null)
{
throw new ArgumentNullException("item");
}
int index = Advertising.FindIndex(p => p.Id == item.Id);
if (index == -1)
{
return false;
}
Advertising.RemoveAt(index);
Advertising.Add(item);
return true;
}
}
}
I have ASP.Net MVC 5 Web API project. I cant use asp.net web API 2 web service in android my web service is under mvc5, Then I have created mobile app in Eclipse Juno and i use Android sdk 21 below is my edited code
There are many issues.
It starts with what looks a little careless "SELECT * FROM tblAdvertising"
That is three sins against the rules of SQL.
First there is no table called tblAdvertising. There is one called dbo.tblAdvertising. So lacking the real name SQL assumes that you mean dbo, but that might be something else as well. This will dump your performance. Best always use fully qualified names.
The second issue is that you use * as items to select. I have been a long in SQL development and can tell from own experience how often tables are changed. The person doing so might not even be aware of your application so a simple add will cause your code to break. Always use fully qualified SQL column names as well.
The final issue with your SQL is that you use a command and yet poke in text strings, even those that are unprotected against SQL injection. What if someone adds this as string "'',0,0; truncate table tblAdvertising; --". You might be surprised how often, certainly in the past i could log in websites simply with some variation of "'' or 1=1 --". Best avoid unprotected strings that go to MSSQL or MySQL or any SQL for that matter. Also your SQLstring needs to be compiled taking a further performance hit. There is also no protection against wrong parameters or proper feedback if the result does not exist.
Besides you really do not want to select an entire table. There should be like a top 100 or you could implement some paging.
So the solution is that you use a proper stored procedure, check the parameter input and provide limited and properly formatted output.
Also your
INSERT INTO tblAdvertising (SearchString, OstanID, AdsGroupID) VALUES (#SearchString, #OstanID, #AdsGroupID)
can be much improved.
If you update or insert there is an output statement in SQL that is massive faster than querying the max number
create type dbo.IntTable as table(i int)
go
create proc dbo.AdvertisementInsert
#SearchString varchar
, #OstanID int
, #AdsGroupID int
, #NewID int = 0 output
as
set nocount on -- important to avoid second roundtrip over the network
declare #i as dbo.IntTable -- use predefined table variable
-- always check quality of input first
if #SearchString is null return 50001
-- also avoid rollback transaction since that is costly.
-- Better to ask first if this not already exist
if exists(select 42 from dbo.tblAdvertising where SearchString = #SearchString) return 50002
INSERT INTO tblAdvertising (SearchString, OstanID, AdsGroupID)
output inserted.Id into #i -- catch new id directly into table variable
VALUES (#SearchString, #OstanID, #AdsGroupID)
-- report the result
select #NewID = i from #i -- convert table variable to single int
go
So now your proc can be called just using the parameters and will tell you back either 0 .. in which case the result code will tell you why it failed, or some other number matching the new identity
Enjoy
The model of my project is database first, and uses remote access to database on another server.
I need to use raw SQL query because my query is very complex and I feel more comfortable in SQl not LINQ.
This is how I do:
string query = "select * from Inquiry_TBL where ...";
using (educationEntities db = new educationEntities())
{
var list = db.Database.SqlQuery<Inquiry_TBL>(query);
ViewData["total"] = list.Count();
}
The problem is sometimes I get the query result within a second, sometimes it just keep loading for a long time and gives me an error that 'Calling 'Read' when the data reader is closed is not a valid operation.'
Why is that? Is there something wrong with my code, or because I'm using remote access to another server? Will switching to local server solve the problem?
The Entity Framework Code First API includes methods that enable you to pass SQL commands directly to the database. You have the following options:
• Use the DbSet.SqlQuery method for queries that return entity types. The returned objects must be of the type expected by the DbSet object, and they are automatically tracked by the database context unless you turn tracking off. (See the following section about the AsNoTracking method.)
• Use the Database.SqlQuery method for queries that return types that aren't entities. The returned data isn't tracked by the database context, even if you use this method to retrieve entity types.
• Use the Database.ExecuteSqlCommand for non-query commands.
Calling a Query that Returns Entities:
public async Task<ActionResult> Details(int? id)
{
if (id == null)
{
return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
}
// Commenting out original code to show how to use a raw SQL query.
//Department department = await db.Departments.FindAsync(id);
// Create and execute raw SQL query.
string query = "SELECT * FROM Department WHERE DepartmentID = #p0";
Department department = await db.Departments.SqlQuery(query, id).SingleOrDefaultAsync();
if (department == null)
{
return HttpNotFound();
}
return View(department);
}
Calling a Query that Returns Other Types of Objects:
public ActionResult About()
{
//Commenting out LINQ to show how to do the same thing in SQL.
//IQueryable<EnrollmentDateGroup> = from student in db.Students
// group student by student.EnrollmentDate into dateGroup
// select new EnrollmentDateGroup()
// {
// EnrollmentDate = dateGroup.Key,
// StudentCount = dateGroup.Count()
// };
// SQL version of the above LINQ code.
string query = "SELECT EnrollmentDate, COUNT(*) AS StudentCount "
+ "FROM Person "
+ "WHERE Discriminator = 'Student' "
+ "GROUP BY EnrollmentDate";
IEnumerable<EnrollmentDateGroup> data = db.Database.SqlQuery<EnrollmentDateGroup>(query);
return View(data.ToList());
}
Calling an Update Query:
[HttpPost]
public ActionResult UpdateCourseCredits(int? credit)
{
if (credit != null)
{
ViewBag.RowsAffected = db.Database.ExecuteSqlCommand(
"UPDATE Course SET Credits = Credits * {0}", credit);
}
return View();
}
For more information have a look at Advanced Entity Framework 6 Scenarios for an MVC 5 Web Application (12 of 12).
Can we return a multiple result set in stored procedure and how to handle it in .net
???
if yes how??
if no why not ??
please explain
If you are retrieving data using DataReader, you can use NextResult method to iterate through multiple resultsets returned by stored procedure. More information can be found here.
The following code is a simple example from MSDN:
static void RetrieveMultipleResults(SqlConnection connection)
{
using (connection)
{
SqlCommand command = new SqlCommand(
"SELECT CategoryID, CategoryName FROM dbo.Categories;" +
"SELECT EmployeeID, LastName FROM dbo.Employees",
connection);
connection.Open();
SqlDataReader reader = command.ExecuteReader();
while (reader.HasRows)
{
Console.WriteLine("\t{0}\t{1}", reader.GetName(0),
reader.GetName(1));
while (reader.Read())
{
Console.WriteLine("\t{0}\t{1}", reader.GetInt32(0),
reader.GetString(1));
}
reader.NextResult();
}
}
}
If you are populating a Dataset from a DataAdapter, note that if DataAdapter encounters multiple resultsets, it will create multiple DataTables (one for each resultset) and will add them to the resulting DataSet.
http://msdn.microsoft.com/en-us/library/yf1a7f4f.aspx has some good examples.
you need to change your connectionString to support it. MultipleActiveResultSets=True
http://msdn.microsoft.com/en-us/library/h32h3abf.aspx for config settings;
Is there a way to use simple sql queries on ASP MVC without using LINQ thing?
any link is welcome :)
Of course, you can always drop down to use regular ol' ADO.NET :-)
The Data Access Application Block is also commonly used to simplify the execution of raw sql and stored procedures.
Sure, you can embed plain ADO.NET objects within your controller's action methods or in a custom business logic library. A bit of an example. WARNING: DEMONSTRATION CODE ONLY. DO NOT ATTEMPT TO USE IN PRODUCTION SCENARIO.
public ActionResult Index()
{
using(SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["CNTax"].ConnectionString))
{
using(SqlCommand command = conn.CreateCommand())
{
command.CommandText = "select * from Names";
command.CommandType = CommandType.Text;
conn.Open();
var table = new DataTable();
table.load(command.ExecuteReader());
return View("Index", table);
}
}
}
A simple code snippet to select all names from the database and return the index view with the model set as a DataTable.
You sure can. And it is done the same way as you normally would in an ASP.NET application just like the other answers here have indicated.
....HOWEVER, I prefer to use a tool to generate my data access layer. Some of the top choices right now are nHibernate, and LLBLGen Pro, or even Microsoft's Entity Framework
I personally would go with nHibernate or LLBLGen Pro, depending on if you want to have your data access layer driven by "domain driven design" (nHibernate) or "data driven design" (LLBLGen Pro)
Building off of #user102220's answer:
Set up a data access layer (just a separate class or series of classes), then call these from your controller. Apply ADO.NET as necessary.
If you are using Entity Framework you can use SqlQuery like this:
using(var db = new DbContext())
{
var result = db.Database.SqlQuery<your object>("Your Query",params));
}
Your object : your expected result Type (object or class Type) and
Your query and params : sql command with params you should pass to query or not
try this solution:
var results = DynamicCall.DynamicListFromSql(_entities, "select * from users", null).ToList();
public static IEnumerable<dynamic> DynamicListFromSql(this DbContext db, string Sql, Dictionary<string, object> Params)
{
using (var cmd = db.Database.Connection.CreateCommand())
{
cmd.CommandText = Sql;
if (cmd.Connection.State != ConnectionState.Open) { cmd.Connection.Open(); }
using (var dataReader = cmd.ExecuteReader())
{
while (dataReader.Read())
{
var row = new ExpandoObject() as IDictionary<string, object>;
for (var fieldCount = 0; fieldCount < dataReader.FieldCount; fieldCount++)
{
row.Add(dataReader.GetName(fieldCount), dataReader[fieldCount]);
}
yield return row;
}
}
}
}