How To Check If Data Already Exists In Database?

Dec 8, 2006

I was able to get this code to work but now I get a SQL error if you try to submit the same information twice. 
How can I add a message saying that the "email" already exists in database without the SQL error?

    protected void Button1_Click1(object sender, EventArgs e)
        SqlConnection conn =
            new SqlConnection("Data Source=TECATE;Initial Catalog=subscribe_mainSQL; User Id=maindb Password=123456; Integrated Security=SSPI");
        SqlCommand cmd = new SqlCommand("INSERT INTO [main] (, [userid], [fname], [lname], [degree]) VALUES (@email, @userid, @fname, @lname, @degree)", conn);
            cmd.Parameters.AddWithValue("@email", email.Text);
            cmd.Parameters.AddWithValue("@userid", uscid.Text);
            cmd.Parameters.AddWithValue("@fname", fname.Text);
            cmd.Parameters.AddWithValue("@lname", lname.Text);
            cmd.Parameters.AddWithValue("@degree", degree.SelectedItem.Value);

            int i = cmd.ExecuteNonQuery();


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Check If Value Exists In Database?

Dec 9, 2006


I'm wondering is there a command that I can use to check if a certain value exists in the database? Something that returns true or false perhaps?

SELECT * FROM Customers WHERE ID ='1'

Ok so that's simple, but how can I return a true or false if '1' is a value that exists in the db?


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Feb 18, 2006

hi. i'm building a news section for some friends of mine. i list all the news items on the main page in a gridview. i've made a custom edit linkbutton that sends the user to an edit page, passing the news id as a quarystring variable. on the edit page i first check if the querystring variable contains an id at all. if not, i redirect the user to the main page. if an id is passed with the querystring, i fetch the matching news item from the database and place it in a formview control for far, so good. but what if someone types a random id in the querystring? then the formview won't show up and i'd look like a fool. :) therefore, i need some kind of check to see if the id exists in the database. if not redirect the user back to the main page... so i started thinking: i could check the databsae in a page_load procedure. if all is well, then display the news item. since the formview is automatically filled with the correct data, does that mean that i call the database two times? i mean, one for checking if the news item exists, and one for filling the formview. logically, this would be a waste of is appreciated.

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How To Check Whether Server Is Exists With Some Table In Particular Database.

May 29, 2006


I want to know through applicaiton how to check whether the Server named"Myserver" is Exists with Database named "MyDatabase" with Tables named ('Table1','Table2','Table3').

For any Database like (MS Access, Oracle, MS SQL-Server,MySQL)..

Please help me.....

thank's in advance.......

Paresh Patel.

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Mar 15, 2008


I am using sqlconnection to connect sqlserver 2005, Before connect the server i want check the server is exists or not, if server is not exist give a prompt to user enter the actual server name,
If there is any way to check whether server exists or not pls

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Integration Services :: Opening A Rowset For Failed - Check That Object Exists In Database

Mar 14, 2014

I have a SSIS package where im importing data from MS access database file .MDB. I chose Microsoft JET 4.0 OLEDB provider. When i select a table and preview the data, im getting the below error.

Error at Data Flow Task [OLE DB Source [1]]: SSIS Error Code DTS_E_OLEDBERROR.  An OLE DB error has occurred. Error code: 0x80040E09.

Error at Data Flow Task [OLE DB Source [1]]: Opening a rowset for "_tblDateDateEarnedMismatch" failed. Check that the object exists in the database.

But it is working for the other tables .

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May 3, 2006


I'm SQL Server 2005 newbie, could you be so kind and help me how to write the most efficient way stored procedure, which checks by PK if specified row exists, then updating the row, otherwise inserting new one.

Thank you for your kind help.

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Check If Record Exists

Feb 1, 2007

 Hello,I created the following SQL script to check if a record exists:IF (EXISTS (SELECT LevelName FROM dbo.by27_Levels WHERE LOWER(@LevelName) = LOWER(LevelName)))  Return (1)ELSE  Return (0)And I also found in a web page another solution:IF EXISTS(SELECT 1 FROM TABLENAME WHERE LevelName=@LevelName)  SELECT 1ELSE  SELECT 0- Which approach should I use?- Why "SELECT 1 FROM"?- And when should I use SELECT or RETURN?All I need is to know if the record exists ... nothing else.I will use this procedure on an ASP.NET 2.0 / C# web site.I am not sure if this important but anyway ...Thank You,Miguel

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Check If Record Exists

Dec 24, 2007

 I was wondering if someone can help.
 In what is the best way to check if a record exists if you are using an sql data reader?
For my application I need to display a button control (make it visible on the page) if a record is available after executing my sql select statement.
Mark :)

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Check Id Exists In Sql Table?

Jan 17, 2008

Hi all,I am in the process of creating a page that checks to see if a particular user exists in the database and if it does then send to welcome.aspx if not then accessdenied.aspx.  The userid is requested from the query string.I have done some research and cannot find anything directly related, I have tried to add bits of code into what i think is the right place but I dont think what i am doing is correct. Can someone help and show me where my code is going wrong? Also is there a better/more efficient way to do what I am doing?Thanks in advance. default.aspx.csusing System;using System.Data;using System.Data.SqlClient;using System.Configuration;using System.Web;using System.Web.Security;using System.Web.UI;using System.Web.UI.WebControls;using System.Web.UI.WebControls.WebParts;using System.Web.UI.HtmlControls;public partial class _Default : System.Web.UI.Page{    protected void Page_Load(object sender, EventArgs e)    {        string UserID = Request.QueryString["uid"];        //string TransferPage;        if (UserID != null)                {            //initiate connection to db            SqlConnection objConnect = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["MyConnection"].ConnectionString);            string sql = "SELECT COUNT(*) FROM members WHERE UserID = '" + UserID + "'";            SqlCommand query = new SqlCommand(cmd, test);            int count = (int)query.ExecuteScalar();            int aantal = -1; // some default value if can't insert record            if (count == 0) // no existing record for username            {                Server.Transfer("accessdenied.aspx");            }            else            {                Session["UID"] = UserID;                Server.Transfer("welcome.aspx");                            }                    }        }} 

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How To Check If Cursor Exists

Jan 27, 2008

Does anybody can tell me how to check if cursor exists ?
 I have a "try and catch" blocks.
I want to destroy the cursor when error occurred and it jumps into "catch" block.
Before I destroy the cursor I want to check if it exists, because the error could occurred before I have declared or opened the cursor.

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Check If Primary Key Exists

Mar 18, 2006


I have created a formview which I among other things uses to insert new values into a database. What I want to check is if the primary key which is put into the form already exists in the db. If it is I want to get a message to my web page, if not the data can be inserted.

How can I do this?

And if the only way to control this is to create a stored procedure. How do I write such a proc?

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Oct 7, 2003

Is there is a piece for code ot sample code that can let me check if a file exists? Has any one done this before?


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Feb 25, 2004

Hi there,

I am quite new to SQL Server and am having a bit of trouble.

I have created a linked server with the datasource an excel spreadsheet.

I am trying to write a bit of T-SQL that basically checks if the linked server exists. If it does do X, if not do Y.

Can anyone help, its driving me bananas!

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May 11, 2004

I declare a cusror named crInv inside a loop.
Since I open this cursor a lot of times I want to check if is already opened.
I try to use the Cursor_status function but it always returns -3.
The syntax is:


If Cursor_Status('local','crInv')>0 BEGIN

This code is inside a loop.
If I PRINT Cursor_Status('local','crInv') before and after the DECLARE statement it always returns -3.
What is wrong??

Best regards,

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May 20, 2008


This my first time using the link server to read the files directly from within SQL2005, so issues the following link:-

EXEC sp_addlinkedserver
@server = N'MYVFPSERVER', -- Your linked server name here
@srvproduct=N'Visual FoxPro 9', -- can be anything
@datasrc=N'"C:PROGRAM FILESMICROSOFT VISUAL FOXPRO 9Samplesdata estdata.dbc"'

After that i can open query and do the import issues, but how can check if the table exists before issues the query.

Best regards

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Jun 5, 2008

Hello all.

Can anyone tell me how to go about establishing if a particular view exists on a table?


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Mar 19, 2007

Hello all.

Can anyone advise me how to check to see if a particual triggers exists through a SQL script?


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May 17, 2007

Is there a way in T-SQL to check to see if a #tempTable exists? I want to write a proc the uses a temp table, but I first need to see if the table already exists. if it does I want to drop it, otherwise skip

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Jul 25, 2006

Hi, can someone tell me how to check if a file exists. If it exists then i want to continue with the process and if it fails then send a mail to me.

Thanks in advane.

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Aug 21, 2006

In SSIS, I need an easy way to see if a file exists, and if not wait for it until a timeout period expires. Here are the options I've discovered, along with the issues I've had:

a) The File Watcher task from

This was my first attempt. The task works great, BUT only detects when there is a change on the file. If the file already exists, it keeps waiting which is not the behavior I need.
b) The WMI Event Task

There is very sparce documentation on this event and how to write a WQL query. There are numerous examples of monitoring a folder and if any files appear, cause an event to happen. I need to detect for a specific file. I found maybe one example of this using "PartComponent" but wasn't able to get the sytax right to make it work for me. I also need to access a remote file share using a UNC path (e.g. \servernamepathfile.txt) which I could not get to work.
c) Script Task using the File.Exists() method

I imported the System.IO namespace, and used a File.Exists(\servernamepathfile.txt) with actual success, but am not sure of the best way to continue to wait if the file is not found immediately. I also want to modularize this approach so I can wait for several files simultaneously so was thinking of implementing this script task as a package by itself to accept variables (filepath & timeout period) but need to know if anyone has had success with this approach.
I'm open to suggestions or ways to get options a) and b) to work for my needs.

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Feb 5, 2007

Well, actually, as in the title. I have a table. The script should add a column if that column doesn't exist already. I use VB to combine the two queries. So what I want:

Query1: Does the column exists:

if No,

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How can I achieve this?

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Aug 27, 2007

Is there any way to check whether the login exists before creating login ?

create login should be executed after check.



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Nov 16, 2004

Hi all,

I have a table where I want to populate it with data (certain fields) from another table. But I only want to populate the table if there is data in a certain field in the table I wish to get the data from.

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Sep 14, 2006

What’s the easiest way to check if a single value exists in a table column?  I’m building a simple login page, and I want to get the username and check if it exists in my Users table. Here’s my SQL: SELECT UserID FROM UsersWHERE UserID = "admin" Could someone give me code to check for “admin” in my UserID column?    Here’s some code I tried, using my SqlDataSource, but it returns an error “Could not load type 'System.Data.OleDb'”     protected void Button1_Click(object sender, EventArgs e)    {        // Retreive the results from the SqlDataSource as a DataReader        OleDbDataReader reader = (OleDbDataReader)              SqlDataSource1.Select(DataSourceSelectArguments.Empty);         // Read in the value        if (reader.Read())        {             }                     // Close the reader        reader.Close();             } I don’t have to use the SqlDataSource, but originally thought it might be easier. I know how to use SqlDataSource to fill a whole GridView but this is different.  

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Jun 17, 2008

Basically, i am still relatively new to and SQL. And i have the following query.
I have a skills table to which the user enters their skills using the following fields: Skillcatagory, SKill, Current Level, Target Level, target date and comments and the serial of the user.
I need to check via our staff table, which people have had a skill entered for them. And then produce a report on who has not had a skill entered for them.
This table has a serial of the user column aswell which is unique.
If there is more information that i can give you to assist me, please ask me.
 You help would be greatly appreciated.

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Apr 10, 2008

Hi there,
I want to create an SQL Function that checks if a table exists and returns true or false. I will pass this function a paramter (say @COMPANYID) e.g.

if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[tblmyTableName_' + @COMPANYID) and OBJECTPROPERTY(id, N'IsUserTable') = 1)

how would I write this so the query is dynamically executed and I can get a value of true or false back?

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Jun 4, 2008

Hello all.

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Thanks people.

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Mar 14, 2007

Hi All.

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Nov 26, 2007

What is the best way to check for an existing table in a db (i.e. check to be performed when creating a table)
I have came accross the following:

Code Block



Code Block
if not exists (select * from dbo.sysobjects where id = object_id('[someUser].[someTable]') and OBJECTPROPERTY(id, 'IsUserTable') = 1)

Note I want to work with tables that can have any name (unicode chars accepted);

I realise that INFORMATION_SCHEMA.TABLES is a view, and views are generally preffered, but why then does enterprise manager create the SQL found in the second example?

If anyone could explain what is best practice, it would be much appreciated,


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Oct 5, 2006


How can I check if a temporary table exists in the current context?

With normal tables I'd do a

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However, I can't do that with a temporary table. I'd have to go look at the sysobjects table in the tempdb database.

The problem is that for temporary tables, a suffix is added to the name to make it unique for each scope. I can't change the WHERE clause to name LIKE 'myTableName%' because this would return true if a temporary table with the same name exists in a different scope.

Any ideas?


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Jun 22, 2007

How to check to make sure a column does not exist before adding it? Be nice to do this in t-sql code instead of using It seems as if the IF NOT EXISTS is not supported in SqlCe 3.1? I am trying to do this but I get the token error:

select *
from Information_SCHEMA.columns
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Is there a list of all CE supported t-sql commands?



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How To Check If A Temporary Table Exists?

Apr 29, 2008

I apologize if this has been asked, and answered, before. I wasn't able to find relevant posts on the forum. A Google search pointed me to a couple of pages that offered this simple recipe:

if object_id('#temp') is not null

print 'table exists';

(I have also tried 'tempdb.#temp', and 'object_id(..,'U'))

Unfortunately, this doesn't work: the condition evaluates to 'false'. #temp is alive and well: strying to 'select .. into' it raises error

> There is already an object named '#temp' in the database.

Thanks a lot!

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