Question

C# variable in MySQL query

Asked by: kiannack55

Is it possible to compare a global C# variable in a MySQL query?

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Asked On
2009-08-04 at 14:02:25ID24626278
Tags

mysql

,

asp.net

,

c#

Topics

MySQL Server

,

C# Programming Language

,

Programming for ASP.NET

Participating Experts
2
Points
250
Comments
24

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Answers

 

by: angelIIIPosted on 2009-08-04 at 14:05:18ID: 25018150

short answer: yes.
long answer: you have (of course) to put the variable into the sql query itself.
mysql, per se, cannot know of a c# variable, global or not global

 

by: TheLearnedOnePosted on 2009-08-04 at 14:13:45ID: 25018207

You can pass the variable value, as a parameter, into a stored procedure call, or in a dynamically created query string.

 

by: kiannack55Posted on 2009-08-04 at 14:16:23ID: 25018235

I'm trying to assign the variable the current user value for custom ASP.net <sharepoint> page. Do I have to assign the parameter in MySQL code? If so how do I embed that on an ASP.net page?

Thanks

 

by: TheLearnedOnePosted on 2009-08-04 at 14:59:16ID: 25018619

We would need a little more information about the context for your question, in order to provide the "best" solution...  

What are you using to execute the MySQL query?  Do you have something like an SqlDataSource, or a .NET data object?

 

by: kiannack55Posted on 2009-08-05 at 05:03:03ID: 25022380

I want to use the StringBuilder variable and compare it to the MACHINE.'USER' in the query.

Thanks

This is the variable:
public static StringBuilder MyStringBuilder2 = new StringBuilder(SPContext.Current.Web.CurrentUser.ToString());
 
This is the query:
<asp:SqlDataSource SelectCommand="SELECT DISTINCT
SOFTWARE.DISPLAY_NAME AS `Some of the Unautorized Programs`
FROM
SOFTWARE
Inner Join SOFTWARE_LABEL_JT ON SOFTWARE.ID = SOFTWARE_LABEL_JT.SOFTWARE_ID AND 1414= SOFTWARE_LABEL_JT.LABEL_ID
Inner Join MACHINE_SOFTWARE_JT ON SOFTWARE_LABEL_JT.SOFTWARE_ID = MACHINE_SOFTWARE_JT.SOFTWARE_ID
Inner Join MACHINE ON MACHINE_SOFTWARE_JT.MACHINE_ID = MACHINE.ID
WHERE
MACHINE.`USER` = variable"

                                              
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by: TheLearnedOnePosted on 2009-08-05 at 14:20:38ID: 25028217

If you have an SqlDataSource, then you can dynamically create the SelectCommand in the Page_Load event handler, or define a parameter.

http://msdn.microsoft.com/en-us/library/z72eefad.aspx

Example:



       <asp:SqlDataSource ID="EmployeesSqlDataSource"  
          SelectCommand="SELECT EmployeeID, LastName + ', ' + FirstName AS FullName FROM Employees" 
          ProviderName="System.Data.OleDb"
          Connectionstring="<%$ ConnectionStrings:NorthwindOleDbConnection %>" 
          RunAt="server">
        </asp:SqlDataSource>
 
 
        <asp:SqlDataSource ID="EmployeeDetailsSqlDataSource" 
          SelectCommand="SELECT EmployeeID, LastName, FirstName, Address, City, Region, PostalCode
                         FROM Employees WHERE EmployeeID = ?"
 
          InsertCommand="INSERT INTO Employees(LastName, FirstName, Address, City, Region, PostalCode)
                         VALUES (?, ?, ?, ?, ?, ?); 
                         SELECT @EmpID = SCOPE_IDENTITY()"
 
          UpdateCommand="UPDATE Employees SET LastName=?, FirstName=?, Address=?,
                           City=?, Region=?, PostalCode=?
                         WHERE EmployeeID=?"
 
          DeleteCommand="DELETE Employees WHERE EmployeeID=@original_EmployeeID"
 
          ProviderName="System.Data.OleDb"
          ConnectionString="<%$ ConnectionStrings:NorthwindOleDbConnection %>"
          OnInserted="EmployeeDetailsSqlDataSource_OnInserted"
          RunAt="server">
 
          <SelectParameters>
            <asp:ControlParameter ControlID="EmployeesDropDownList" PropertyName="SelectedValue"
                                  Name="EmpID" Type="Int32" DefaultValue="0" />
          </SelectParameters>
 
          <InsertParameters>
            <asp:Parameter Name="LastName"   Type="String" />
            <asp:Parameter Name="FirstName"  Type="String" />
            <asp:Parameter Name="Address"    Type="String" />
            <asp:Parameter Name="City"       Type="String" />
            <asp:Parameter Name="Region"     Type="String" />
            <asp:Parameter Name="PostalCode" Type="String" />
            <asp:Parameter Name="EmpID" Direction="Output" Type="Int32" DefaultValue="0" />
          </InsertParameters>
 
          <UpdateParameters>
            <asp:Parameter Name="LastName"   Type="String" />
            <asp:Parameter Name="FirstName"  Type="String" />
            <asp:Parameter Name="Address"    Type="String" />
            <asp:Parameter Name="City"       Type="String" />
            <asp:Parameter Name="Region"     Type="String" />
            <asp:Parameter Name="PostalCode" Type="String" />
            <asp:Parameter Name="original_EmployeeID" Type="Int32" DefaultValue="0" />
          </UpdateParameters>
 
          <DeleteParameters>
            <asp:Parameter Name="original_EmployeeID" Type="Int32" DefaultValue="0" />
          </DeleteParameters>
 
        </asp:SqlDataSource>
                                              
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by: kiannack55Posted on 2009-08-06 at 10:53:09ID: 25036152

I've researched more on parameters thanks to your help. I'm having trouble assigning the parameter the HttpContext.Current.User.Identity.Name value;. I tried displaying the HttpContext.Current.User.Identity.Name value and it works and assigned the parameter a static value and that too worked with the query. When I pass the parameter into the query don't get any results.

Thanks

<asp:Parameter DefaultValue="<%=HttpContext.Current.User.Identity.Name.ToString()%>" Name="UserNo" Type="String" /> 
                                              
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by: TheLearnedOnePosted on 2009-08-06 at 12:28:18ID: 25037197

Did you look at the value returned from HttpContext.Current.User.Identity.Name.ToString(), to see if it is what you expect?

 

by: kiannack55Posted on 2009-08-06 at 12:44:59ID: 25037349

Yes it returns DOMAIN\username

 

by: TheLearnedOnePosted on 2009-08-06 at 12:50:59ID: 25037407

Did you define the parameter, and modify the SqlDataSource.SelectCommand to use the new parameter?

 

by: kiannack55Posted on 2009-08-06 at 13:24:02ID: 25037647

Yes.

<asp:SqlDataSource runat="server" id="SqlDataSource2" ProviderName="System.Data.Odbc"  ConnectionString="Server=kbox;Database=ORG1;DSN=***;UID=***;PWD=***; port=3306;Option=3;" 
SelectCommand="SELECT
Count(SOFTWARE.DISPLAY_NAME),
MACHINE.`USER`
FROM
SOFTWARE
Inner Join SOFTWARE_LABEL_JT ON SOFTWARE.ID = SOFTWARE_LABEL_JT.SOFTWARE_ID AND 1413
= SOFTWARE_LABEL_JT.LABEL_ID
Inner Join MACHINE_SOFTWARE_JT ON SOFTWARE_LABEL_JT.SOFTWARE_ID = MACHINE_SOFTWARE_JT.SOFTWARE_ID
Inner Join MACHINE ON MACHINE_SOFTWARE_JT.MACHINE_ID = MACHINE.ID
WHERE
(MACHINE.USER_LOGGED = ?)
GROUP BY
MACHINE.`USER`
">
 
<SelectParameters>
  <asp:Parameter DefaultValue="<%=HttpContext.Current.User.Identity.Name%>.ToString()" Name="UserNo" Type="String" /> 
     </SelectParameters>
</asp:SqlDataSource>
                                              
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by: TheLearnedOnePosted on 2009-08-06 at 13:28:44ID: 25037700

You aren't using named parameters, so I am not sure if that will find a match, and set a value.  You can find out by testing in the SqlDataSource.Selecting event handler:

Example:

Bind Data From a SqlDataSource to a Label
http://www.mikesdotnetting.com/Article/64/Bind-Data-From-a-SqlDataSource-to-a-Label

protected void SqlDataSource1_Selecting(object sender, SqlDataSourceSelectingEventArgs e)
{
      e.Command.Parameters["EmployeeID"].Value = 2;
}

You can see that it is possible to set the parameter value in that event handler, before the data is selected.

 

by: kiannack55Posted on 2009-08-06 at 14:04:16ID: 25038038

The parameter is named its after the DefaultValue. The query returned the correct result when I put static text into the DefaultValue of the param

 

by: TheLearnedOnePosted on 2009-08-06 at 15:04:22ID: 25038551

Sorry, I meant not named in the query:

    (MACHINE.USER_LOGGED = ?)

 

by: kiannack55Posted on 2009-08-10 at 05:37:14ID: 25059325

When I use sample text "Domain\username" instead of HttpContext.Current.User.Identity.Name.ToString() it works when using a "?".

 

by: kiannack55Posted on 2009-08-10 at 06:05:18ID: 25059532

I tried using <asp:ProfileParameter Name="username" PropertyName="username" /> and still nothing.

 

by: TheLearnedOnePosted on 2009-08-10 at 08:12:01ID: 25060639

Did you examine, and try to set the parameter in the Selecting event handler, as shown above?

 

by: kiannack55Posted on 2009-08-10 at 09:58:38ID: 25061695

I tried but I am still unsure how to do it. When I try to implement it on an .aspx page I get this error: An error occurred during the compilation of the requested file, or one of its dependencies. The type or namespace name 'DataView' could not be found (are you missing a using directive or an assembly reference?). But I am unable to put "using System.Data;" at the top of the page.

 

by: TheLearnedOnePosted on 2009-08-10 at 10:07:57ID: 25061772

If you have a web page without a code-behind .cs file, then you put using statements like this:

      <%@ Import Namespace="System.Data" %>

 

by: kiannack55Posted on 2009-08-10 at 10:23:51ID: 25061924

I keep getting "An unexpected error has occurred." when I try to load the page.

protected void Page_Load(object sender, EventArgs e)
{
 
	DataView dvSql = (DataView)SqlDataSource1.Select(DataSourceSelectArguments.Empty);
	foreach (DataRowView drvSql in dvSql)
	{
		Label1.Text = drvSql["MACHINE.USER_LOGGED"].ToString();
	}
 
	}
 
 
 
protected void SqlDataSource1_Selecting(object sender, SqlDataSourceSelectingEventArgs e)
{
	e.Command.Parameters["MACHINE.USER_LOGGED"].Value = "DOMAIN\\username";
}
                                              
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by: TheLearnedOnePosted on 2009-08-10 at 10:26:08ID: 25061949

Can you give me a hint where that error might be occurring?

 

by: kiannack55Posted on 2009-08-10 at 10:34:19ID: 25062031

I modified the code from the link you posted. Are the info in the brackets[ ]  supposed to be the names of the tables in the database? Can you use casting like (DataView)SqlDataSource1.Select(DataSourceSelectArguments.Empty) for Strings?

Thanks

 

by: TheLearnedOnePosted on 2009-08-10 at 10:37:02ID: 25062070

The SqlDataSource.Select method executes the underlying SqlCommand, and the type that is returned depends on how the SqlDataSource is defined.

SqlDataSource.Select Method
http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.sqldatasource.select.aspx

"The Select method returns a DataView object if the DataSourceMode property is set to the DataSet value. The Select method returns a IDataReader object if the DataSourceMode property is set to the DataReader value. Close the IDataReader object when you have finished reading the data."

 

by: kiannack55Posted on 2009-08-25 at 11:00:31ID: 25180320

The data binding did work. Thanks a lot. For anyone thinking about doing something similar here's the code.

<script type="text/c#" runat="server">
void Page_Load(Object sender, EventArgs e) {	
Session["UserName"] = SPContext.Current.Web.CurrentUser.ToString(); //For current sharepoint user
GridView3.DataBind();
}
</script> 
 
 
<asp:SqlDataSource runat="server" id="SqlDataSource1" ProviderName="System.Data.Odbc" ConnectionString=""  SelectCommand=
"SELECT DISTINCT
SOFTWARE.DISPLAY_NAME AS `Unauthorized Programs`
FROM
SOFTWARE
Inner Join SOFTWARE_LABEL_JT ON SOFTWARE.ID = SOFTWARE_LABEL_JT.SOFTWARE_ID AND 1414= SOFTWARE_LABEL_JT.LABEL_ID
Inner Join MACHINE_SOFTWARE_JT ON SOFTWARE_LABEL_JT.SOFTWARE_ID = MACHINE_SOFTWARE_JT.SOFTWARE_ID
Inner Join MACHINE ON MACHINE_SOFTWARE_JT.MACHINE_ID = MACHINE.ID
WHERE
MACHINE.USER_LOGGED = ?
">
<selectparameters>
		<asp:sessionparameter name="UserName" sessionfield="UserName" type="String" />
</selectparameters>
                                              
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