c# windows appliaction & database

Anita Mathew

I am making a windows application that will check if a database exists on the local server? if it does'nt then create it through the program ..

here is the part of the program :

private void checkdbexists_Click(object sender, EventArgs e)

{

string sqlCreateDBQuery;

bool result = false;

SqlConnection tmpcon =new SqlConnection("Server= ...-PC;Integrated security= True; Initial Catalog= ....");

try

{

sqlCreateDBQuery = string.Format(" select databaseID from sys.databases where Name

= '{0}'", databasename);

using (tmpcon)

{

using (SqlCommand cmd = new SqlCommand(sqlCreateDBQuery, tmpcon))

{

tmpcon.Open();

object resultObj = cmd.ExecuteScalar();

int databaseID = 0;

if (resultObj != null)

{

int.TryParse(resultObj.ToString(), out databaseID);

}

tmpcon.Close();

result = (databaseID > 0);

label4.Text= " Database already exists";

}

catch (Exception ex)

{

result = false;

label4.Text = " Database does not exist";

}

return result;

}

but it gives me the following errors :

1. Newline in constant for : sqlCreateDBQuery = string.Format(" select databaseID from sys.databases where Name

= '{0}'", UPSC );

2.return keyword must not be followed by an object expression for: return result;

need help to get the code running..

8 Replies

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Saroj Kumar Sahu11y ago
please check the below url for this error:

http://www.sswug.org/articlesection/default.aspx?TargetID=44331

http://stackoverflow.com/questions/18060667/cannot-connect-to-server-a-network-related-or-instance-specific-error
+1
Anita Mathew11y ago
thank u for patiently helping..the program has made some progress..but then it gives this error now.. A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified)

is there something wrong in this line: SqlConnection tmpcon =new SqlConnection("Server= ...-PC;Integrated security=........
0
Saroj Kumar Sahu11y ago
Its because u had manually try to change the event return type and again created one more event.
So Remove both the event and control from the form and redesign it again.
0
Anita Mathew11y ago
this.checkdbexists.Click += new System.EventHandler(this.checkdbexists_Click_1);

gives a squiggly line below this in the designer.cs
0
Anita Mathew11y ago
Error 2 'bool WindowsFormsApplicationup.Form1.checkdbexists_Click_1(object, System.EventArgs)' has the wrong return type C:\Users\anita\documents\visual studio 2010\Projects\WindowsFormsApplicationup\WindowsFormsApplicationup\Form1.Designer.cs 145 41 WindowsFormsApplicationup
Error 1 'WindowsFormsApplicationup.Form1.checkdbexists_Click_1(object, System.EventArgs)': not all code paths return a value C:\Users\anita\documents\visual studio 2010\Projects\WindowsFormsApplicationup\WindowsFormsApplicationup\Form1.cs 134 22 WindowsFormsApplicationup
0
Anita Mathew11y ago
thanks for replying.. whern i remove the line it gives the error : not all code paths return a value..and i did make it private bool..
0
Saroj Kumar Sahu11y ago
Hi Anita,

For first error: you eed to check the string format.
second:your event handler is not returning anything but in your code last line you are returning vlue.so please remove the return line.

Or please try the below code:

private void checkdbexists_Click(object sender, EventArgs e)
{
if (!IsDatabaseExists())
{
//Your code for create database
}
}

private bool IsDatabaseExists()
{
string sqlCreateDBQuery;
bool result = false;
SqlConnection tmpcon = new SqlConnection("Data Source=server;Integrated security= false;User ID=sa;Password=***;");
try
{
sqlCreateDBQuery = string.Format("SELECT database_id FROM sys.databases WHERE name='{0}'"," databasename");
using (tmpcon)
{
using (SqlCommand cmd = new SqlCommand(sqlCreateDBQuery, tmpcon))
{
tmpcon.Open();
object resultObj = cmd.ExecuteScalar();
int databaseID = 0;
if (resultObj != null)
{
databaseID = Convert.ToInt32(resultObj);
}
tmpcon.Close();
result = (databaseID > 0);
if (result)
{
label1.Text = "Database already exists";
}
}
}
}
catch (Exception ex)
{
result = false;
label1.Text = "Database does not exist";
}
return result;
}

0
Manoj Bhoir11y ago
Hi,

For you first error, If you will execute below query on your database.
select * from sys.databases
You will see column database_id there is no column like databaseID.
So your query should be like this :
sqlCreateDBQuery = string.Format("Select database_id From sys.databases Where name = '{0}'", databasename);
Now for second error :
private void checkdbexists_Click(object sender, EventArgs e)
Here return type is void and below you are writing return result;
So either make change from void to bool by creating new function or remove return line. because function always return value not method.
0