ASP.NET Web PDF Document Viewer/Editor Control Library

ROLLBACK TO <SAVEPOINT>: This statement is used with the SAVEPOINT command. You can roll back your transaction to that marked point without rolling back any of the work that preceded it. So, you could issue two UPDATE statements, followed by a SAVEPOINT and then two DELETE statements. If an error or some sort of exceptional condition occurs during execution of the DELETE statements, and you catch that exception and issue the ROLLBACK TO SAVEPOINT command, the transaction will roll back to the named SAVEPOINT, undoing any work performed by the DELETEs but leaving the work performed by the UPDATE statements intact. SET TRANSACTION: This statement allows you to set various transaction attributes, such as the transaction s isolation level and whether it is read-only or read-write. You can also use this statement to instruct the transaction to use a specific undo segment when using manual undo management, but this is not recommended. We ll discuss manual and automatic undo management in more detail in 9 Redo and Undo.

ssrs code 128 barcode font, ssrs code 39, ssrs fixed data matrix, winforms pdf 417 reader, winforms qr code reader, winforms upc-a reader, itextsharp remove text from pdf c#, replace text in pdf using itextsharp in c#, winforms ean 13 reader, c# remove text from pdf,

That s it there are no other transaction control statements. The most frequently used control statements are COMMIT and ROLLBACK. The SAVEPOINT statement has a somewhat special purpose. Internally, Oracle uses it frequently; in fact Oracle uses it every time you execute any SQL or PL/SQL statement, and you may find some use for it in your applications as well.

type WebReferences.TerraService with member ws.GetPlaceFactsAsyncr(place) = Async.BuildPrimitive(place, ws.BeginGetPlaceFacts, ws.EndGetPlaceFacts) These have the following types: member ws.GetWeatherByPlaceNameAsyncr : placeName:string -> Async<WeatherForecast> member ws.GetPlaceFactsAsyncr: place:string -> Async<PlaceFacts> We can now define various asynchronous tasks using these primitives. For example, we can define a function getWeather that collects both the weather and position data for a given location but executes the two calls simultaneously. let getWeather(city,state,country) = async { let ws = new WeatherForecast() let ts = new TerraService() let place = new Place(City=city, State=state, Country=country) let! weather,facts = Async.Parallel2 (ws.GetWeatherByPlaceNameAsyncr(city), ts.GetPlaceFactsAsyncr(place)) let today = weather.Details.[0] return (today.MinTemperatureF,today.MaxTemperatureC, facts.Center.Lat,facts.Center.Lon) } The type of this function is as follows:

Consider the following statement: Insert into t values ( 1 ); It seems fairly clear that if the statement were to fail due to a constraint violation, the row would not be inserted. However, consider the following example, where an INSERT or DELETE on table T fires a trigger that adjusts the CNT column in table T2 appropriately: ops$tkyte%ORA11GR2> create table t2 ( cnt int ); Table created. ops$tkyte%ORA11GR2> insert into t2 values ( 0 ); 1 row created. ops$tkyte%ORA11GR2> commit; Commit complete. ops$tkyte%ORA11GR2> create table t ( x int check ( x>0 ) ); Table created. ops$tkyte%ORA11GR2> create trigger t_trigger 2 before insert or delete on t for each row 3 begin 4 if ( inserting ) then

One simple use of this task is to run it and print the results when the operation completes: Async.Run (async { let! (maxF,maxC,lat,lon) = getWeather("Los Angeles","CA","USA") do printfn "Temperature: %sF/%sC" maxF maxC do printfn "Lat/Lon: %f/%f" lat lon }) With an active web connection, this results in output such as the following (after a short delay while the connections are resolved): Temperature: 100F/38C Lat/Lon: 33.833000/-118.217003

5 update t2 set cnt = cnt +1; 6 else 7 update t2 set cnt = cnt -1; 8 end if; 9 dbms_output.put_line( 'I fired and updated ' || 10 sql%rowcount || ' rows' ); 11 end; 12 / Trigger created. In this situation, it is less clear what should happen. If the error occurs after the trigger has fired, should the effects of the trigger persist, or not That is, if the trigger fired and updated T2, but the row was not inserted into T, what should the outcome be Clearly the answer is that we don t want the CNT column in T2 to be incremented if a row is not actually inserted into T. Fortunately in Oracle, the original statement from the client INSERT INTO T, in this case either entirely succeeds or entirely fails. This statement is atomic. We can confirm this, as follows: ops$tkyte%ORA11GR2> set serveroutput on ops$tkyte%ORA11GR2> insert into t values (1); I fired and updated 1 rows 1 row created. ops$tkyte%ORA11GR2> insert into t values(-1); I fired and updated 1 rows insert into t values(-1) * ERROR at line 1: ORA-02290: check constraint (OPS$TKYTE.SYS_C0018095) violated ops$tkyte%ORA11GR2> select * from t2; CNT ---------1

Note When using SQL*Plus from Oracle9i Release 2 and before, in order to see that the trigger fired, you need

Summary

to add a line of code, EXEC NULL, after the second INSERT. This is because SQL*Plus does not retrieve and display the DBMS_OUTPUT information after a failed DML statement in those releases. In Oracle 10g and above it does.