I have an ASP.NET project and would like to create a page where my system admins can modify database table data (insert, update, and delete rows).
First, I have a drop down that is databound based on the tables in the database:
DdlTable.DataSource = from x in dc.Mapping.GetTables()
orderby x.TableName.Replace("dbo.", "")
select new {TableName = x.TableName.Replace("dbo.", "")};
DdlTable.DataTextField = "TableName";
DdlTable.DataValueField = "TableName";
DdlTable.DataBind();
DdlTable.Items.Insert(0, "Select a Table");
Next, I would like to have a gridview (or some other data object) that is bound to a table upon selection, and have the columns, insert, update, and delete functionality built dynamically. Can this be done without coding for each specific table?
Obviously, I can create x number of gridviews and datasources, but I would like it to be built dynamically for flexibility and minimal coding.
Essentially, I want to have a simple web-based SQL manager.
Try...
Create a seperate datasource for each table (in code or mark-up, doesn't matter).
Make sure the gridview doesn't have a datasource set when the page loads.
On some event (button click, selectedindexchanged of your dropdown, etc.), set the gridview's datasource to whichever datasource is selected in the dropdown, make sure autogenerate = true, and then databind().
In short - no - you change your tables, you have to change your CRUD - there's no magic bullet.
You can try something like CodeSmith. Or you can just write something yourself -- shouldn't be too difficult, should it? Query the InformationSchema view for your table's fields and you have all of the information you need to build a function in your code-behind to generate the CRUD statements.
Related
I need help choosing between Telerik RadGrid and DevExpress ASPxGridView for Asp.Net based on unique filtering requirements. The data lives in denormalized Vax files. All data access is via Sql Server stored procedures calling ODBC Connx queries to the flat files. Stored procedure parameters are used to filter the data. Without any filter thousand of records are returned.
I've successfully displayed all records on two test ASP.net pages, one with DevExpress ASPxGridVIew and the other with Telerik's RadGrid. In code I databind each grid to the stored procedure that returns over 26,000 rows. The sproc is called via an Entity Framework function import that fills an IEnumerable<Customer> which becomes the datasource of each respective grid. I'm able to use the filter features of both grids and they seem to work nicely.
My problem is that before the grid filter is applied all of the thousands of rows are returned from the stored procedure. I'd like to intercept the grid's filter parameters and apply them to my stored procedure parameters. That way far fewer records will be accessed.
Can this be done with either 3rd party grid and if so how?
Thanks in advance.
It seems it can be achieved using a RadFilter to the RadGrid. One example here.
But in general, looks like you'd need to add a handler to ItemCommand, and perform the appropriate filter based on the CommandName, for example. You could then just rebind the data.
The Rad Filter will also allow you to use it without being directly tied to another control or datasource. The filter has an option to extract a filter expression in many different forms (linq provider is one of them). You can then apply that expression to your datasource. We are doing something similar. We have a page where we dynamically create the rad filter with the types of fields and filter options. The user then uses the rad filter UI to create the filter based on the desired fields, then we extract a filter expression we can apply to a datatable that is created on the page that shows the data.
Here is the code for extracting the filter expression from the filter:
var provider = new RadFilterSqlQueryProvider();
provider.ProcessGroup(myRadFilter.RootGroup);
var sqlFilterExpression = provider.Result;
I have a column and I would like to edit some of its rows. The problem is that the table is a view so I cannot edit the rows. How would I proceed to solve this problem?
SQLite doesn't let you update views. But it does allow triggers on views. So you can write an INSTEAD OF UPDATE trigger that makes the appropriate modifications to the underlying table.
As dan04 pointed out, you can use triggers to update views (like in most other databases). For sqlite, see http://www.sqlite.org/lang_createtrigger.html#instead_of_trigger
Example with a view called "myview", containing a table "my_t2"
CREATE TRIGGER myview_update INSTEAD OF UPDATE ON myview
BEGIN
UPDATE my_t2 SET field1 = new.field1, field2 = new.field2 WHERE my_t2.key = old.key;
END
If it's a view, it's not a table. The data for the view is drawn from one or more other tables. Edit the underlying table and when you examine the data in the view it will reflect the changes you made.
A SQL View is a virtual table, which is based on SQL SELECT query. Essentially a view is very close to a real database table (it has columns and rows just like a regular table), except for the fact that the real tables store data, while the views don’t. The view’s data is generated dynamically when the view is referenced. A view references one or more existing database tables or other views. In effect every view is a filter of the table data referenced in it and this filter can restrict both the columns and the rows of the referenced tables.
If you wish to modify the data in your table, you cannot do so with a view. SQL Views are always read-only. If you want to modify your table outside of the View, then use something like an UPDATE or ALTER TABLE statement.
I have a database and I've created a DBML Linq-to-SQL file to represent this database. I've created a new aspx page and dropped a linqdatasource and a formview control onto it. When I configure the linqdatasource it gives me the choice only to select * from one table...but I want to pull from multiple tables. e.g. I have tables like simple_person, simple_address, simple_phone, and I want to pull from all of them. How can I accomplish this?
Use a custom query
http://weblogs.asp.net/scottgu/archive/2007/09/07/linq-to-sql-part-9-using-a-custom-linq-expression-with-the-lt-asp-linqdatasource-gt-control.aspx
See: Using the <asp:LinqDataSource> Selecting Event
I recently began working on a project which has many gridviews on a single page. During creation of a new record, the user needs to be able to add/remove/edit these gridviews and then save to the database at the end. The problem with this obviously is that there is no datasource to bind the data too until after its written to the database.
This data represents a 1..* relationship, which is why the gridview data cannot be written to the database until the parent record has been created first.
The best way I have found so far to solve this is to use viewstate. This solution however does not seem ideal to me. I am also forced to manually create the gridview functionality with OnDeleting, OnUpdating, etc so that I can manage the binding of the viewstate with the gridview.
Does anyone have any suggestions on a better way to manage this situation, it seems like it would be a common thing?
UPDATE:
Keep in mind this data needs to be around throughout postbacks.
Use a DataSet as an intermediate connection to your data source. Fill the DataSet with your data and then bind your GridView to the DataSet setting the GridView DataMember to the name of the table it is supposed to bind to.
As the user updates tables it will add/modify records in the DataTables in the DataSet. When the user is done editing and clicks "Save" your code can then update the database from the datasets, either automatically using a DataAdapter, or manually looking at the RowState of the rows in the DataTables.
Use a DataAdapter and a Dataset. Invoke the fillschema method in the adapter to create de metadata (cols, constraints, relations, etc) in the dataset. bind the data tables created to the different grid views. update manually cheking each row rowstate on each table or call the adapter's update method to do it automatically. If you do it automatically you need to define commands for insert, delete, and update in the adapter.
I'm making an ASP.NET Web Forms application. I would like to get a DataSource which takes its data from a DataTable, and this table is persisted among requests (preferably in session, not ViewState).
The idea is that there is a need for some fairly complex forms where there are several gridviews in each of them. All the gridviews have to have edit functionality (we're using DevExpress), but there has to be one giant "SAVE" button on the form, which saves everything.
So it would be nice if I could get some kind of a DataSource that I could bind these GridViews against and which would only store the data in memory. When the user clicks the Save button I would then manually query these DataSources and extract the changed data from them.
Is there something existing for this, or must I write my own (seems to be a pretty large task)?
The scenario you have described;
Retrieve data from datasource and
store in datatable
Store datatable
in session-state.
Modify datatable
from different grids
Sounds like it will work, issues that i can see you having is that you'll have to reload the data between grids when the data changes. You'll have to write a class that'll raise events when changes are made to the datatable (which you'll probably also want to include in the class, and just store the class object in session state).
I hope the datatable isn't too too big... as this isn't the sort of approach i'd take for a web app.