I am writing my first database application in c# and I have to use MS Access database, I have two tables Invoice and Order the order table is a child table. Invoice is a parent table it has key column "InvoiceNumber" which is auto column and it has a one to many relation with Order table column "InvoiceNumber". The problem I am having is that I got an exception at the line
tableAdapterManager.UpdateAll(database1DataSet);
when I try to add a new row and click save,
"You cannot add or change a record because a related record is required in table 'Invoice'."
I tried to search but I am unable to find it any help for ms access database, most of them are of SQL database. I also found one solution to edit the relation in the dataset designer to select the option "Both relation and foreign key constraints" but it didnot work for me either.
Thanks
Make sure that your OleDbParameters are properly set and in the correct corresponding order as the columns in the tables in the database. If you use Visual Studio automated code generation for data sources when you add a database, then drag and drop a table onto a form, check out the <database name>DataSet.Designer.cs file. It will teach you all you need to know.
Related
I'm creating some tables using a Local based database in Visual Studio and I have 2 tables : DBAppointment (parent) and DBPatient (child).
What I'm trying to do is to specify the on delete cascade action (so when I'm deleting a record from the child table, the parent table record containing the id of the child table record should be removed) but I can't really find where this option is.
Any idea?
Read this Microsoft article first. Read Me. I use the GUI during design so here is a picture of how it is selected in SSMS.
The syntax added to the foreign key is " ON DELETE CASCADE "
Hope this will be useful for you.
If you're using Entity Framework with Code First Approach in your EfContext you can set .WillCascadeOnDelete(true);
See Working With Cascade Delete
I had created new tables but when I click update model from database, the new tables werent added. I tried setting primary keys and all, but it couldnt work too. And when I click the update model from database, in the dialog box, the "add" column, I selected Table but none of the tables stated there. So when I click finish, none of the new tables is being added to the model. I dont know why my tables not shown in the add column. Anyone know what is wrong with it?
Can't comment yet so I'll ask my question as an answer. Under the add tab, did you check the checkboxes for the table that you wanted to add? Secondly after you have added do you see your tables in the edmx file?
I have a crystal report file with header and footer placeholders. The report is connected with 3 tables. 2 tables are connected with foreign key and the 3rd table is only information of the company or other data which will be get on runtime from user acquired and in DataSet saved.
How can I join these three tables. Because it refuses to put tables on one report without relationship between all of them.
Need some more guidance on what could be done here to achieve this.
Thanks.
One option you can try is to use Sub reports.
Take the table that is isolated in sub report and other two tables that are connected with foreign key in main report.
By this you can solve the issue.
Let me know if you need more information.
First Point Is there Any Common Columns Between the Table ?
if Not Insert One table That contain Columns Between the table
then It will Automatically Link all the Tables
I am using SQLite DB to store data in my c# project. I have an existing table which has some records. Now I want to insert two more columns in existing table. How can I insert the data with my C# code for those two columns. Do I need to create the table again or altering the table will do?
The project also has designer.cs corresponding to that table which is getting generated automatically. I want to know how this file is getting generated.
for changing to schema in sqlite u need to make appropriate changes in .XSD file in your project. This will change the designer.cs automatically and ur schema will be changed. You can search ".xsd" in ur project and can go ahead.
What does this icon mean is Visual studio, visual Data Set designer.
I have several stored procedures.
can you help me understand,
why the one on top of the list has a
small "check mark"
why I can't delete it if I need to.
This is not the case with the rest.
Why is this "special" ?
Thanks
Because that item contains the method(s) that define the schema of the table the TableAdapter is part of.
The default names are Fill and GetData. Looks like you renamed them.
Each table has a default query (The one on top with the check on it). When you dragged your tables in to the dataset to create the query, it wrote a SQL statement which it uses to schema your table. Keep that query simple, you might not actually use it in code, and you can always edit that query to update the table schema. In the picture you provided, your default query is actually a stored procedure.
Every time you open the default query it connects to your datasource and allows you to select new columns that weren't in there before. If you want to update your existing columns, delete all the columns out of the table before you attempt to open the query. When you save the query, your updated columns get added back.
Make sure your connection string has permissions to view column information.