I have an event posted from firebird database in a trigger after a new record is inserted like this: post_event 'SPOOL' + new.username;
I want to register this event with SIBfibEventAlerter (FIBPlus) in a Delphi application and run a procedure. Problem is that event name depends on user name added the record.
You could read the usernames from the user table (if new.username is actually a field and not some FB system value) and create the eventalerters components dynamically, one per user name.
Since events don't really support parameters, one way would be to add extra fields to table, which contain auto incremental id (or timestamp) and the data you need as a parameter.
Related
My interface is very basic. It just includes edits for the user to input data into a database, when they click the button i want it to add the data into my database.
You can easily do this.
Go to the Data Controls tab of the Component palette.
Select a TDBEdit and place it on the same form as your DBNavigator. The IDE will name this DBEdit1
Set the Datasource property of your DBEdit1 to the same datasource as your DBNavigator.
Set the DataField property of DBEdit1 to the name of a field in your dataset.
Compile and run.
That's it. Leave your DBNavigator on your form because you will find that when you make a change to the contents of DBEdit1, its Save and Cancel buttons automatically enable to let you save or cancel the change.
Also, you'll find that if you click your DBNavigator's '+' button, which begins the insertion of a new record into your table, you can then type the field values for the new record into your DBEdits.
Don't use normal non-DB-aware TEdit components and a dynamically-created Sql statement which concatenates the TEdits's contents with other Sql as suggested in the other answer which briefly appeared here and now seems to have been deleted - it is a waste of time, but much more importantly renders your app vulnerable to Sql-Injection - see https://en.wikipedia.org/wiki/SQL_injection. By sending the server an unverified Sql statement which includes what the user has typed into a TEdit, you're effectively providing the user with an opportunity to type additional Sql statements into the TEdit and that is exactly how Sql injection can occur. On the other hand, when you use TDBEdits, the Sql for updating the database record is automatically generated by Delphi's TDataSet framework in a way which does not provide a similar opportunity for Sql Injection.
If some reason you absolutely have to generate your own Sql Update statements, to minimise the risk of Sql Injection, make sure that you use a parameterised Update statement, that is, one where the changed field values are specified as values of parameters in your TDataSet-descendant's Parameters object, rather than in the Update Sql itself. An example of a parameterised Update statement might be:
Update MyTable set FieldA =:FieldA, FieldB=:FieldB where RowID =:RowID
where :FieldA, :FieldB and :RowID are the parameters.
I have a (Firebird) DB. For most of my tables I have a trigger which fires before insert which will create the Primary Key (PK) for me via a generator as well as write to the newly inserted records a Created Date value and a Created By value. I also have an update trigger which writes to an Updated Date field and an Updated By field.
eg (Client is a table in my DB):
create trigger t_client_id for client
active before insert
as begin
new.client_id = gen_id(gen_client_id, 1);
new.created = current_timestamp;
new.created_by = current_user;
new.lock_vn = 1;
end ^
create trigger t_client_update for client
active before update
as begin
new.updated = current_timestamp;
new.updated_by = current_user;
end ^
When I apply updates thru my ClientDataSet (CDS) - which are attached to remote TDataSetProviders via a TDSProviderConnection, how can I "retrieve" these generated values? If I edit an existing one (which will in turn call the t_client_update trigger, calling RefreshRecord will get the updated and updated_by fields. However, the Doco says to use that method cautiously, so that may not be the correct way to achieve this. I call it straight after I've called ApplyUpdates(-1).
The CDS I use only contains the one record I am attempting to Edit. For a New record, the CDS is in dsInsert mode. Everything is written to the DB ok so I just need to get this new data back out again. I have also tried using a CDS which contains ALL records in the table too to see if it was any simpler but didn't make any difference - unsurprisingly. The reason I need this information is simply to show to the user in DB Aware controls these values. They are read only.
I could call a Get on the record I guess when editing an existing record, using the PK, but that won't help for an Insert as I don't know what the new PK is.
Example of where I attempt to ApplyUpdates to my CDS (actDSSave is a TDataSetPost action)
dsState := actDSSave.DataSource.DataSet.State;
DoApplyUpdates(-1);
if dsState = dsEdit then
TClientDataSet(actDSSave.DataSource.DataSet).RefreshRecord;
I am using TIBQuery for my dataset attached to the remote DataSetProvider. This query SQL is a simple select * from client where client_id = :client_id. I have tried associating this query with a TIBUpdateSQL too as well as trying to set poAutoRefresh to true in the DataSetProvider.
So is it possible to obtain these Trigger generated values this way or do I need to approach it in a different way? Another way I can think of, is to create stored procedures which do CRUD against each table and use that instead (with appropriate in/out params to return this new data) but hopefully I don't have to go down that track. Hopefully I have provided sufficient info here to explain and replicate the issue.
Thanks
EDIT
Realised in above, DoApplyUpdates(-1) is my own method. It's implementation at the moment is simply:
FdatCommon.cdsClient.ApplyUpdates(MaxErrorCount);
FdatCommon is a TDataModule containing my CDS.
You simply can't get "generated" values without new requery (RefreshRecord) of data after Post.
It's because triggers runs on server side when you call ApplyUpdates, but TClientDataSet does not refresh by default posted record. For example other libraries FIBPlus have an option to do it automatically.
About inserts, TIBDataSet have GeneratorField property. Using it, dataset query and increment generator value separatelly before insert. So you will have PK values after post even on inserts. But avoid using it again in trigger.
MIDAS (TClientDataSet) is a great library, but his general / universal architecture loose DB specific features (such as retriving values from inserts) compared to dedicated libraries for specific DBMS, such as FibPlus. By the way I saw TpFIBClientDataSet. It work in conjunction with TpFibDataSet.
Is there a way to auto increment a number field in a WITT (e.g. Bug). We've got a requirement that we want contiguous Bug ids (note - not its actual id but a separate field).
Can this field be done unique per collection OR unique per project (thus duplicates would occur in the collection).
---edit
I've no idea how to tackle this, but I'm wondering if I could use a globalist, e.g. bug creation triggers the adding (replacement) of a value to the list?
There is no way to do this directly through the WIT platform. You would need to write some sort of custom service to do this for you on the creation of a new bug.
My answer goes into the same direction like aaronbjorks one.
Create a webservice that gets alerted if a new bug is created, then just write down the bug ID in a database with an identity column. On the workitem you can create a custom control, that gets the identity for that bug from the database and displays it somewhere.
A possible workaround would be exporting your items query to Excel and let it update the IDs upon Publish. Make sure once an ID was assigned, tag it as FROZEN.
I have an application in Delphi 7 which is using a clientdataset, and make several operations on it. ClientDataSet is linked to an Intraweb Grid.
I make an insert or an edit on the ClientDataSet. How can I verify the data introduced in the clientdataset for each field? I can not verify the input from the user on the webform, so I must make validation using ClientDataSet events.
LE: I want to validate data when the user make the input. Not at the onbeforepost event. So, I put the clientdataset in the edit/insert. User make an input in the grid, and I want to validate the data for that row in the clientdataset like in the image bellow:
first column is string, second is integer, the third one is also an integer. Now, I want to validate the third column after the user make the input. This validation must be done (if it is possible), only by using clientdataset events/hacks.
You should handle TClientDataset BeforePost event, and if data is not valid use abort method
TField has an OnValidate event for that purpose. It has also a CustomConstrain property that can use a SQL like syntax for constraints. DefaultExpression will let you select a value if no value is given. These are usuful for single-field validation. If you need more complex checks across more than one field, then you have to use dataset or datasource events.
Anyway, if the Intraweb grid sends the server whole records and not single fields edits, you may not validate fields as they are entered in the grid but adding code client side.
If you want a field based validation, you can handle the OnDataChange event of the TDatasource connecting the grid to the dataset. This will be triggered whenever a field has been changed by the user. You should be aware that it will also be triggered in some other situations.
I'm coming from the delphi world and I want to make a master/detail interface, like Order and Products.
I already made actions to display the data using fields and a jqGrid. What I want know is how make possible to add lines, edit or remove them, but, just make the changes in db when the user confirm the changes in the master.
On delphi I would use a TClientDataSet with all the in memory changes and just after the confirmation would execute them inside a transaction like:
BEGIN
Master.Post
FOREACH Line IN Lines Line.Post
COMMIT
So in resume, I don't know how keep in memory the array of lines in the grid and how send them back to server to commit.
Any help will be appreciated. Thanks in Advance.
You'll need to keep track of the changes client side, perhaps using some hidden fields and/or form fields in your grid. When a line is deleted (that previously existed in the db), you'll need to add it's id to a field containing lines to delete. Lines that are added need to have associated form fields containing their data. When the master is committed you roll the whole set of fields up into a POST and send that back to the server.
Using LINQ to SQL, you'd create a data context, get the master object, then delete the related objects (from the hidden field of ids) that are so marked and create/add new related objects that didn't exist before taking the values from the appropriate form fields. Then you'd do a SubmitChanges and all of the statements would be executed within a single transaction.