DataSource Controls :: How To Create A Constraint For 3 Columns
Jun 4, 2010
I want to create a constraint for 3 columns (A B and C) where if columns B or C are not null, then A cannot be null. And vice versa (i.e., if A is not null, then either B cannot be null, or C cannot be null).I am not very well versed in SQL and would like to know what is the best way to achieve this (e.,g Check constraint, stored procedure, function, trigger)? I'm leaning towards trigger but I'm not 100% sure if that's right nor of how to implement it.
I have a SQL Server 2000 table with 7 columns and would like to add a constraint that prevents a row being added with the same value for both Col2 and Col3.
So, for example, if Col2 = 205 and Col3 = 5, then the constraint should prevent inserting another row with the values for Col2 = 205 and Col3 = 5.
The following is an example of what I would like to prevent:
STUDENT PARENT student_id (PK) parent_id (PK) student_parent (FK) parent_status (the value is either ACTIVE OR INACTIVE)
- parent_id is refer by STUDENT table as a foreign key
- now i want to inactive the status for parent
- i want my system pop out a message something like "The parent you want to inactive is refer by a student, inactive is not allow"
- is it any constraint in SQL Server 2005 to help me check whether parent it is refer by student table? The concept i want to use is something like delete constraint in SQL Server 2005 mean it is not allow to delete a person who is refer by a student in STUDENT table.
The DELETE statement conflicted with the REFERENCE constraint "FK_EquipmentStatus_MeetEquip". The conflict occurred in database "D:MEETINGROOMAPAPP_DATADATABASE.MDF", table "dbo.EquipmentStatus", column 'Fk_MeetEquip'.
I'm getting this error when i'm trying to delete a listboxitem. It's true that an other table (EquipmentStatus) is using the primary key attached to the listboxitem, but how can i delete all the rows that causes this problem? I've seen an example using stored procedure, but i dont understand it, since i haven't really worked with it before:
ALTER TABLE t2 DROP CONSTRAINT FK_t1id
ALTER TABLE t2 ADD CONSTRAINT FK_t1id FOREIGN KEY (t1id) REFERENCES t1 (t1id) ON DELETE CASCADE
My listbox is using MeetEquip table which p-key is MeetEquip.ID, and the fk-key (which generates the problem) is fk_MeetEquip from EquipmentStatus table.
I'm new to asp.net and I'm building a project in which I send data to a database MSSQL, I've set a constraintname on some fields that I wantto be unique, now how do I catch that error when people insert a duble and handle it with a redirectionto custom error pagehere the code just in case you need it
Dim con As New System.Data.SqlClient.SqlConnection con.ConnectionString = "Data Source=localhost;Initial Catalog=Database1;User ID=user;Password=password;TrustServerCertificate=True" Dim myCommand As New System.Data.SqlClient.SqlCommand myCommand.CommandText = "INSERT INTO serves(CategoryID,UserId,vote, Img, link, Description) VALUES('" & DropDownList1.SelectedValue & "','" & UId.Text & " ' ,1,'" & TextBox1.Text & "','" & "<a href=" + TextBox2.Text + ">" + TextBox4.Text + "</a>" & "','" & TextBox3.Text & "')" myCommand.Connection = con con.Open() myCommand.ExecuteNonQuery()
I created a gridview that is made up of 4 gridviews and using a stored procedure to populate it. I create columns at runtime because the number of columns changes all the time.To make the grids editable I am adding template fields at runtime as I create the columns, this is to ensure that a user is able to edit the cells and some foot values update. Reason why I have four grids is to freeze rows and columns like in excel using javascript. The problem is that performance is very bad especially in IE, the grids take a long time to load. I am not sure if this is caused by the data load or the creation of text boxes. see some of the code below for my _aspx page:
I"m using table adapters here. I tried to use the following in my table adapter:
ALTER TABLE tblAdvanceLInk DROP FOREIGN KEY FK_tblAdvanceLink_tblLink DELETE FROM [tblAdvanceLink] WHERE WebsiteID=@WebsiteID
The DELETE statement conflicted with the REFERENCE constraint "FK_tblAdvanceLink_tblLink". The conflict occurred in database "LinkExchanger", table "dbo.tblAdvanceLink", column 'LinkID'. The statement has been terminated
I get the same problem every time. So I read you could do this in a sql query. Why doesn't this work in my tableadapter? Do I have this in the right place? Do I also put this into the other table? (tblLInk) Isn't there a way to just relax ALL constraints so I can delete some rows? I'm deleting rows from both tables which have the corresponding websiteID
I have a datasource, which includes many columns, idealy, I need use a gridview to show:
1) first 3 columns: template fields, these fields depends on values in some columns of datasource. I use template fields, hard coded. works fine.
2) the other columns. This is I do not know how to do it. In the data source, there are about 10-20 columns data, each time, the # of columns of the data varies. idealy, I need show each of them as a seperated column in gridview. The entire data source may have 30 columns, but some of them are used in 1), and I only want show these 10-20 columns in gridview. Some columns in data source, I may not use them at all. is there a way to do this? or have to seperate them as a detail view style UI?
Here is the situation:I have a Datagrid which is going to display a number of rows. I want to click a button on the datagrid and have the following occur
open a row underneath the row clicked, without hiding or replacing that row Open this row so that it spans all of the columns as one continuous row where i can put form fields and/or just data formatted as I would like and not just in columns.Be able to close that new row. While I do most of my work in VB.NET, don't think that is a requirement for answering this.I have managed to currently take the first column (with the "Edit" button) and when clicked to Hide the rest of the cells in that row Expand the button column to run all the way across the table Unfortunately I loose the clicked row's data, and I've only started getting this to work so I haven't tried too much, or getting data to bind to fields "on the fly"
Iam working on an asp.net application.Recently client come with new requirement. Need a control which is similar to table or like gridview with rows and columns.It should allow user to enter data in the cells. And when the user press tab it should go to next cell and finally if we press enter key, it should validate the data entered in the current row and if data is correct it should create a new empty next row(like entering data manually in an sqlserver table). How can i implement this functionality? Can i use gridview / javascript to implement this functionality.
I have a table, that contains a number of rows, in each row there are three columns that are mutually exclusive. What I need is to be able to have radio buttons that are linked across the three columns.
I'd like for where there is a 1 for it to display a checked radio button, and where there is a 0 for it to be unchecked. This can then be edited by clicking the radio in another column where necessary.
I want to know that how many tables we can have in database and what is the maximum no. of columns.I also want to know the maximum size for each datatype.
I need to join some tables to get the matching records. I often have to ask around to see how certain tables could be joined. Is there any way to query the information schema or some thing else to see what columns/values match in certain tables in order to figure out how tables should be joined.
I have a DataSet that I bind to a GridView control. I want to only show certain columns from the DataSet. Should I do that with my SQL query (that I use to populate my DataSet) or somehow with a DataView?
is there a SQL statment i could write that would sum each column and allow me to then access each sum individually
i.e
Dim objCmd As New OleDb.OleDbCommand("SELECT SUM(expression) FROM orderForm WHERE OrderDate=@OrderDate", objConn)
is there anything i can replace expression with such that all the columns in orderForm could be summed and returned as one record
or is there a way to replace expression with something that would allow me to just keep changing the paramater so i could continuously reexectute the same command w/o having to create a new command for each column
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]...
