Asp net updating database from dataset chace crawford dating 2016
This is the scenario (Delphi XE2 32 bit, I have attached a small text file that contains code snippets related to this question): - One Access database (single table) used with a TADOQuery - All records are SELECTed with a very simple SQL statement - A Quantumgrid with three views, but for the moment we can concentrate on the first view only that is very plain vanilla The cell layout is: - One unbound checkbox (Greyed not allowed) inserted as the first cell and as explained in one of the questions found here - The checkboxes are all set to checked at startup (see attached code) - The datacontroller of this view has Immediate Post = True and also the checkbox has Immediate Post = True since I want that the state changes with only one mouse click. It works without problems and I can check and uncheck rows just as I wanted.
Datasets store a copy of data from the database tables.
As you know, there are frequent modifications in database tables in real life.
These may include insertions, updates and deletions.
Everything is working properly except for when I update the data set. I have checked the Categories class and there is no method that looks remotely close to the Find By Category ID method. Thanks Hi, Can you verify if the Category ID is the primary column in your database table? One option is to set the primary column in the table and regenerate the dataset. Update(data Set11); The error I recieved was as follows: Invalid Operation Exception: Update requires a valid Update Command when passed Data Row collection with modified rows I was able to fix it by adding the following line before the Update command: System.
I am unable to call a 'find' method that the walkthrough claims should have been generated automatically: // Finds the row in the dataset table that matches the // one the user updated in the grid.
We would explore later that there is no need of opening and closing database connection explicitly while you deal with Data Adapter objects. For the moment I am interested only in the Quantumgrid.Anyway I have to say that the learning curve is very steep.However, Datasets can not directly retrieve data from Databases.Data Adapters are used to link Databases with Data Sets.