I know this is a newbie question but, alas , that's what I am. How do I keep values in specifc sql server table unique, in other words how do I prevent any duplicates happening upon creating (inserting) a new table row?
Is it possible to allow repeated nulls on a column with a unique constraint? This column will won't always be populated with data upon insert, a condition must be met before the value is update. Once updated, it needs to be unique. Do I need to assign a temporary, random value or
I need a way to create unique values for a property in my custom server control..
In this case I will have the poroperty called "Name" and I neeed the value of Name to be unique for each "instance" of the control...
So for instance if I have a page with more then one instance of the control, I dont want the value of the Name property for these instances to be allowed to be the same..
...to put it kind of simple, if I dont remember this incorrect, I want it to be sort of like the ID property..but with another name then ID.
I have a table converted from Access and the identity keys were lost. Now I need to make the id column the identity column, but it already has a lot of null values, how do I auto generate integer values for the null rows? The row ids are incremented, so if there is a way to auto increment the ids
I have a sql table which has one row of value. In my application i want to rename the column name as the first row values. I am using as keyword but waht do i put after 'as' for the first row values
I need to loop through an XML document (no problem over there) and check if a value that i find is already in a (a) tag in a div in my XSL document that i am generating, only if the value is not in that (a) tag i should create a new (a) tag for it and put in in the div that i am checking... how to do it dynamically in XSLT?
I am returning a dataset from a method and trying to set one of the columns as Primary Key.
CategoryList.Tables[0].PrimaryKey = new DataColumn[] { CategoryList.Tables[0].Columns["CategoryNodeId"] };
Interestingly it gives me this error at run-time, These columns don't currently have unique values.
Now I perfectly know why this error should error, but there are no duplicate keys in this data column. I broke the code in between and bound the dataset to gridview to check if this column contains any duplicates and this is not the case. Here is the result set underneath. Have a look at the first column 'CategoryNodeId'.
CategoryNodeId CategoryId Name ParentCategoryNodeId [code]...
I'll try to make this concise. Anyways, I'm trying to only allow unique data to my database. my database. What I did before adding the entry is to use a Search Query for the value of the txtbox
"SELECT IDnum WHERE IDnum = '" & txtID & "'"
Then compare it with that of the txtbox.
IF objReader("IDNum") <> txtID.textbox then add the entry Else Display a Warning.
in the above code, I can detect the when the user entered an existing value. however, If the user entered a NEW (unique) value an error is Raised "Invalid attempt to read when no data is present" I hit the wall with this.So what I did, Since I can detect Duplicates and have errors when entering unique value, I used the
ON ERROR GOTO statement: I did it like this.
On Error Goto errHandler
If objReader("IDNum") = txtID.textbox then lbl1.text = "Existing Record" objReader.close() [code]....
The Code does what I need but its kinda long, I bet there is an elegant way to do this.
I've got a database table with a very large amount of rows. This table represents messages that are logged by a system. Each message has a message type and this is stored it it's own field in the table. I'm writing a website for querying this message log. If I want to search by message type then ideally I would want to have a drop down box listing the message types that have come up in the database. Message types may change over time so I can't hard code the types into the drop down. I'll have to do some sort of lookup. Iterating over the entire table contents to find unique message values is obviously very stupid however being stupid in the database field I'm here asking for a better way. Perhaps a separate lookup table which the database occasionally updates listing just the unique message types that I can populate my drop down from would be a better idea.
The platform I'm using is ASP.NET MVC and SQL Server 2005
How does System.Guid.NewGuid() know that the values it generates are unique, for example when i use in a loop?Does it internally store data somewhere? .
I am using a datalist to display data from a database.Except for 1 column all the other column values are getting repeated so I am hiding all the other column values when the datalist repeats itself.However, the unique column value is not getting rendered properly because there are many line breaks in between.I am not using any web control to display the static text and I am not sure if that would help.I just want to improve the final display so that the datalist looks consistent.I am attaching my code.
This is my UserRoleList.aspx.cs Code where i am passing the session variable to the page Default.aspx.cs..
And the error is: Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign-key constraints. I have gone through many pages , and tried by making the AllowDbNull property making True and then different things.
using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; using System.Data;
[code]...
This is the code of the second page Default.aspx.cs where i have to user the session varaible to pass in the SQL fucntion named GetDataByUserId as shown below:
using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls;
Now the issue is that that every document doesn't has document number. I want to make invisible the docuNumber column of the grid viwe if all values in the docNumber retrieved are null.for example:
docnumber tite null Document 1
null Document 2
null doucment 3
null document 4
if returned result match above where all docnumber are null then make the gridviwe docnumber column ivisible eslemake the greidviwe column visible.