I've recently started working in ASP.NET and RDBMS.I'm making a test form where I can do basic add,update,delete operations.I'm using OracleDataClient to do the DB operations.I was able to populate a listbox using OracleDataAdapter.
Now after clicking on update button,I intend to Update in DB.I've Dataadapter with it's update property.But the update query is not happening.The examples I saw over net all have Select command before Update.Is it actually like that or am I missing some point.
How does Oracle DataClient work with Insert,Update,Delete Commands.
keep it in datalist or temporary table like data table or Hash table....display data in datalist and for update operation use (1)the proper query (2) command Behaviour (3) check the connection and Dml command operation (4) CommandBehavior
Related
I have to code a script in Teradata that will accept a database-name as an input parameter and then will drop and re-create all the tables that exist in the database (ie passed as the input parameter).
If necessary, it is also good to create a UNIX script with an input parameter that would log-in to the Teradata server and accomplish the same (drop and then recreate), in which case I would want to log the ddls in a file before dropping and recreating them.
Any help is appreciated.
Thanks
I have an MLOAD job that inserts data from an Oracle database into a Teradata database. One of the things it does it drop the destination table and recreate it. Our production website populates a dropdown list based on what's in the destination table.
If the MLOAD script is not on a single transaction then it's possible that the dropdown list could fail to populate properly if the binding occurs during the MLOAD job. If it is transactional, however, it would be a seamless process because the changes would not show until the transaction is committed.
I checked the dbc.DBQLogTbl and dbc.DBQLQryLogsql views after running the MLOAD job and it appears there are several transactions occurring within the job, so it would seem that the entire job is not done in a single transaction. However, I wanted to verify that this is indeed the case before I make assumptions.
A transaction in Teradata cannot include multiple DDL statements, each DDL must be commited seperatly.
A MLoad is treated logically as a single transaction even if you see multiple transactions in DBQL, these are steps to prepare and cleanup.
When your application tries to select from the target table everything will be ok (unless it's doing a dirty read using LOCKING ROW FOR ACCESS).
Btw, there might be another error message "table doesn't exist" when the application tries to select. Why do you drop/recreate the table instead of a simple DELETE?
Another solution would be a loading a copy of the table and use view switching:
mload tab2;
replace view v as select * from tab2;
delete from tab1;
The next load will do:
mload tab1;
replace view v as select * from tab1;
delete from tab2;
And so on. Of course your load job needs to implement the switching logic.
The short version:
I have a grid view bound to a data source which has a SelectCommand with a left join in it because the FK can be null. On Update I want to create a record in the FK table if the FK is null and then update the parent table with the new records ID. Is this possible to do with just SqlDataSources?
The detailed version:
I have two tables: Company and Address. The column Company.AddressId can be null. On my ascx page I am using a SqlDataSource to select a left join of company and address and a GridView to display the results. By having my UpdateCommand and DeleteCommand of the SqlDataSource execute two statements separated by a semi-colon I am able to use the GridView's Edit and Delete functionality to update both table simultaneously.
The problem I have is when the Company.AddressId is null. What I need to have happen is have the data source create a record in the Address table and then update the Company table with the new Address.ID then proceed with the update as usual. I would like to do this with just data sources if possible for consistency/simplicity sake. Is it possible to have my data source do this, or perhaps add a second data source to the page to handle some of this?
Once I have that working I can probably figure out how to make it work with the InsertCommand as well but if you are on a roll and have an answer for how to make that fly as well feel free to provide it.
Thanks.
execute two statements separated by a
semi-colon
I don't see any reason why it wouldn't be possible to do both an INSERT and UPDATE in two statements with SqlDataSource just like you are doing here.
However, just so you know, if you have a lot of traffic or users using the application at the same time, you can run into concurrently issues where one user does something that affects another user and unexpected results can cascade and mess up your data. In general, for things like what you are doing - INSERT and UPDATE involving primary or foreign keys, usually SQL TRANSACTIONs are used. But, you must execute them as SQL stored procedures (or functions), on your SQL database. You are still able to call them from your SqlDataSource however by simply telling it that you are calling a stored procedure.
I'm unable to retrieve the latest inserted id from my SQL Server 2000 db using a typed dataset in asp.NET
I have created a tableadapter and I ticked the "Refresh datatable" and "Generate Insert, Update and Delete statements". This auto-generates the Fill and GetData methods, and the Insert, Update, Select and Delete statements.
I have tried every possible solution in this thread
http://forums.asp.net/t/990365.aspx
but I'm still unsuccesfull, it always returns 1(=number of affected rows).
I do not want to create a seperate insert method as the auto-generated insertCommand perfectly suits my needs.
As suggested in the thread above, I have tried to update the InsertCommand SQL syntax to add SELECT SCOPY_IDENTITY() or something similar, I have tried to add a parameter of type ReturnValue, but all I get is the number of affected rows.
Does anyone has a different take on this?
Thanks in advance!
Stijn
I decided to give up, I can't afford to waste any more time on this.
I use the Insert statement after which I do a select MAX(id) query to hget the insert ID
If anyone should have a solution, I'll be glad to read it here
Thanks
Stijn
I successfully found a way to get the incremental id after insert using my table adapter.
My approach is a little different, I'm using a Store procedure to make the insert, so my insert command has all the values but the ID, I made the sp return the ID just calling:
SET #ID=SCOPE_IDENTITY()
and then
COMMIT TRAN
and last line will be
RETURN #ID
Then I searched my table adapter parameters for InsertCommand and set the #RETURNVALUE to the column of the incremental ID of the table, so when it's executed automatically put the return value on the id field.
Hope this help
You need to tell your table's table-adapter to refresh the
data-table after update/insert operation.
This is how you can do that.
Open the properties of TableAdapter -> Default Select Query -> Advnaced options. and Check the option of Refresh the data table. Save the adapter now. Now when you call update on table-adapter, the data-table will be updated [refreshed] after the update/insert operation and will reflect the latest values from database table. if the primary-key or any coloumn is set to auto-increment, the data-table will have those latest value post recent update.
Now you can Call the update as TableAdapterObj.Update(ds.dataTable);
Read latest values from the DataTable(ds.dataTable) coloumns and assign respective values into the child table before update/insert. This will work exactly the way you want.
alt text http://ruchitsurati.net/files/tds1.png
I have table on a database on a server, that is identical to a table on my local. I have click once application that needs to download the version of records on the server down to my local.
At the moment i have webservice that pulls back the records on the server in batches, using asp.net datasets as containers. How do i commit the whole dataset to the table in my local? The table on my local is empty.
Cheers in advance!
If you already have a DataSet, containing one or several DataTables, why don't you just use the SqlDataAdapter and call its ".Update()" method with your DataSet?
In the SqlDataAdapter, you can define an InsertCommand, an UpdateCommand, a DeleteCommand which will take care of the three basic insert/update/delete statements for your rows. All you need to do is define / write those three SQL Statements once, and the SqlDataAdapter will do the rest for you (looping through the rows, figuring out whether to insert, update or delete etc.).
If you want, you can even use your basic SELECT statement from the SelectCommand in your DataSet and use the SqlCommandBuilder to build the INSERT, UPDATE and DELETE statements based on your SELECT.
MSDN Library doc on SqlDataAdapter
SQL Data Adapter without SqlCommandBuilder
MSDN Library doc on SqlCommandBuilder
Marc
There are several options. Here are the first two that come to mind.
One would be to loop through the DataTable and build an SQL Insert statement on each loop and then execute the Insert statement against the local.
Another would be to use the SQL Bulk Copy to insert the data