I am trying to perform a SELECT on the M1lhao table of Sorteio entity (database).
I don't want to go the traditional "string query" or AddWithParameter() way, i wanted to use the MVC4 EF5 available methods.
The following code passes the entire Table to the View, that i can do a foreach in the View and all works fine. What i am looking for is how can i do a SQL query, so i can pass only the element(s) i want, sorted DESCending (for example), obviously on a List and obeying the Model that the View expects.
Essentially i want a replacement for (i tried variants too, db.Milhao, etc):
var data = db.Database.ExecuteSqlCommand("SELECT * From M1lhao WHERE DrawID = {0}", id);
The problem with Find() is that it only searches primary keys.
The complete code:
public class M1lhaoController : Controller
{
private Sorteio db = new Sorteio();
public ActionResult Index(int id = 1)
{
var data = db.Database.ExecuteSqlCommand("SELECT * From M1lhao WHERE DrawID = {0}", id); // the variable data comes as -1
M1lhao m1lhao = db.M1lhao.Find(id);
if (m1lhao == null)
{
return HttpNotFound();
}
return View(db.M1lhao.ToList());
}
}
Thank you.
You can try as shown below.
var data = db.M1lhao.Where(m=>m.DrawID == id).Select(p=>p);
You can learn more about Method-Based Query Syntax : Projection
I'm aware I need to use Restrictions.Eq and Projections.SqlFunction, but I've been trying for hours without any success (my test app just crashes). Does anyone have an QueryOver example that would do the following in Oracle:
SELECT
*
FROM
V_LOG_ENTRIES
WHERE
regexp_like(ENTRY_TEXT, '(\WPlaced\W)');
UPDATE: Okay, I think part of the problem is that Restrictions.Eq expects an equality, but there is no equality in this case, it's just a function call in the WHERE clause...
The syntax should be like this:
// this is inlined string, but could be concatenated from some params
var sql = #" regexp_like(ENTRY_TEXT, '(\WPlaced\W)') " +
" AS isLike";
var sqlString = new SqlString(sql);
// the ICriterion
var criterion = new NHibernate.Criterion.SQLCriterion(sqlString
, new string[] {}
, new IType[] {}
);
// the query
var query = session.QueryOver<LogEntry>()
.Where(criterion)
...
In RavenDB (build 2330) I'm trying to order my results by the string length of one of the indexed terms.
var result = session.Query<Entity, IndexDefinition>()
.Where(condition)
.OrderBy(x => x.Token.Length);
However the results look to be un-sorted. Is this possible in RavenDB (or via a Lucene query) and if so what is the syntax?
You need to add a field to IndexDefinition to order by, and define the SortOption to Int or something more appropriate (however you don't want to use String which is default).
If you want to use the Linq API like in your example you need to add a field named Token_Length to the index' Map function (see Matt's comment):
from doc in docs
select new
{
...
Token_Length = doc.TokenLength
}
And then you can query using the Linq API:
var result = session.Query<Entity, IndexDefinition>()
.Where(condition)
.OrderBy(x => x.Token.Length);
Or if you really want the field to be called TokenLength (or something other than Token_Length) you can use a LuceneQuery:
from doc in docs
select new
{
...
TokenLength = doc.Token.Length
}
And you'd query like this:
var result = session.Advanced.LuceneQuery<Entity, IndexDefinition>()
.Where(condition)
.OrderBy("TokenLength");
Using Dapper-dot-net...
The following yields no results in the data object:
var data = conn.Query(#"
select top 25
Term as Label,
Type,
ID
from SearchTerms
WHERE Term like '%#T%'",
new { T = (string)term });
However, when I just use a regular String Format like:
string QueryString = String.Format("select top 25 Term as Label, Type, ID from SearchTerms WHERE Term like '%{0}%'", term);
var data = conn.Query(QueryString);
I get 25 rows back in the collection. Is Dapper not correctly parsing the end of the parameter #T?
Try:
term = "whateverterm";
var encodeForLike = term => term.Replace("[", "[[]").Replace("%", "[%]");
string term = "%" + encodeForLike(term) + "%";
var data = conn.Query(#"
select top 25
Term as Label,
Type,
ID
from SearchTerms
WHERE Term like #term",
new { term });
There is nothing special about like operators, you never want your params inside string literals, they will not work, instead they will be interpreted as a string.
note
The hard-coded example in your second snippet is strongly discouraged, besides being a huge problem with sql injection, it can cause dapper to leak.
caveat
Any like match that is leading with a wildcard is not SARGable, which means it is slow and will require an index scan.
Yes it does. This simple solution has worked for me everytime:
db.Query<Remitente>("SELECT *
FROM Remitentes
WHERE Nombre LIKE #n", new { n = "%" + nombre + "%" })
.ToList();
Best way to use this to add concat function in query as it save in sql injecting as well, but concat function is only support above than sql 2012
string query = "SELECT * from country WHERE Name LIKE CONCAT('%',#name,'%');"
var results = connection.query<country>(query, new {name});
The answer from Sam wasn't working for me so after some testing I came up with using the SQLite CONCAT equivalent which seems to work:
string sql = "SELECT * FROM myTable WHERE Name LIKE '%' || #NAME || '%'";
var data = IEnumerable data = conn.Query(sql, new { NAME = Name });
Just to digress on Sam's answer, here is how I created two helper methods to make searches a bit easier using the LIKE operator.
First, creating a method for generating a parameterized query, this method uses dynamic: , but creating a strongly typed generic method should be more desired in many cases where you want static typing instead of dynamic.
public static dynamic ParameterizedQuery(this IDbConnection connection, string sql, Dictionary<string, object> parametersDictionary)
{
if (string.IsNullOrEmpty(sql))
{
return null;
}
string missingParameters = string.Empty;
foreach (var item in parametersDictionary)
{
if (!sql.Contains(item.Key))
{
missingParameters += $"Missing parameter: {item.Key}";
}
}
if (!string.IsNullOrEmpty(missingParameters))
{
throw new ArgumentException($"Parameterized query failed. {missingParameters}");
}
var parameters = new DynamicParameters(parametersDictionary);
return connection.Query(sql, parameters);
}
Then adding a method to create a Like search term that will work with Dapper.
public static string Like(string searchTerm)
{
if (string.IsNullOrEmpty(searchTerm))
{
return null;
}
Func<string, string> encodeForLike = searchTerm => searchTerm.Replace("[", "[[]").Replace("%", "[%]");
return $"%{encodeForLike(searchTerm)}%";
}
Example usage:
var sql = $"select * from products where ProductName like #ProdName";
var herringsInNorthwindDb = connection.ParameterizedQuery(sql, new Dictionary<string, object> { { "#ProdName", Like("sild") } });
foreach (var herring in herringsInNorthwindDb)
{
Console.WriteLine($"{herring.ProductName}");
}
And we get our sample data from Northwind DB:
I like this approach, since we get helper extension methods to do repetitive work.
My solution simple to this problem :
parameter.Add("#nomeCliente", dfNomeCliPesquisa.Text.ToUpper());
query = "SELECT * FROM cadastrocliente WHERE upper(nome) LIKE " + "'%" + dfNomeCliPesquisa.Text.ToUpper() + "%'";
I am using the System.Linq.Data library provided here - http://weblogs.asp.net/scottgu/archive/2008/01/07/dynamic-linq-part-1-using-the-linq-dynamic-query-library.aspx
I have the following query which works great and returns an Iqueryable
IQueryable customer =
ctx.Customers.Where(cust => true).Select("new("Name,Address")");
However, how do I access these returned columns? I cannot access them using a lambda expression as follows:
var test = customer.Where(cust=>cust.Name == "Mike").First();
"cust.Name" in the above case cannot be resolved. It does not exist in the list of methods/properties for "cust".
Am i assuming something wrong here. I understand that I am working with an anonymous type. Do I have to create a DTO in this case?
For any IQueryable you have property called ElementType.
You can use it to get the properties as explained below
IQueryable query = from t in db.Cities
selec new
{
Id = t.Id,
CityName = t.Name
};
if(query!=null)
{
Type elementType = query.ElementType;
foreach(PropertyInfo pi in elementType.GetProperties())
{
}
}
Try foreach loop:
var a = _context.SENDERS.Select(x=>new { Address=x.ADDRESS, Company=x.COMPANY });
foreach(var obj in a)
{
Console.WriteLine(obj.Address);
Console.WriteLine(obj.Company);
}