birt barcode tool Transaction Isolation Levels in Objective-C

Implementation Data Matrix 2d barcode in Objective-C Transaction Isolation Levels

Private Sub MissingBuyerName_ExecuteCode(ByVal sender As System.Object, ByVal e As System.EventArgs) MsgBox("Buyer Name is required when entering a Purchase Order") End Sub Private Sub ExpectedDateInPast_ExecuteCode(ByVal sender As System.Object, ByVal e As System.EventArgs) MsgBox("When entering a Purchase Order expected date must be in the future") End Sub Private Sub OrderQuantityNotGreater0_ExecuteCode(ByVal sender As System.Object, ByVal e As System.EventArgs) MsgBox("When entering a Purchase Order the quantity must be greater than 0") End Sub When the entire workflow is built, there will be many activities within the workflow, which might make it a little difficult to read and understand. Make sure your last two IfElse activities look as they do in Figure 3-10.

Regardless of which object pool strategy is implemented, the interface IObjectPool<> has to be implemented, and is defined as follows: public interface IObjectPool< type> { type GetObject(); void SetFactory( IPoolableObjectFactory< type> factory); bool ReturnObject( type obj); } The interface IObjectPool<> has three methods: GetObject, SetFactory, and ReturnObject. The method GetObject retrieves an object from the pool. The method SetFactory assigns a factory to the object pool collection. And the method ReturnObject is called by the pooled object to indicate that the object is available for reuse. The factory assigned by the method IObjectPool<>.SetFactory is defined as follows:

new XElement("Employee", // First employee element new XElement("Name", "Bob Smith"), new XElement("PhoneNumber", "408-555-1000") ), new XElement("Employee", // Second employee element new XElement("Name", "Sally Jones"), new XElement("PhoneNumber", "415-555-2000"), new XElement("PhoneNumber", "415-555-2001") ) ) ); Console.WriteLine(employeeDoc); } } This code produces the following output: <Employees> <Employee> <Name>Bob Smith</Name> <PhoneNumber>408-555-1000</PhoneNumber> </Employee> <Employee> <Name>Sally Jones</Name> <PhoneNumber>415-555-2000</PhoneNumber> <PhoneNumber>415-555-2001</PhoneNumber> </Employee> </Employees> // Displays the document

We ve covered the files used by Oracle, from the lowly but important parameter file to data files, redo log files, and so on. We ve taken a look inside the memory structures used by Oracle, both in the server processes and the SGA. We ve seen how different server configurations, such as shared server versus dedicated server mode for connections, will have a dramatic impact on how memory is used by the system. Lastly, we looked at the processes (or threads, depending on the operating system) that enable Oracle to do what it does. Now we are ready to look at the implementation of some other features of Oracle, such as locking, concurrency controls, and transactions.

The using statement helps reduce the potential problem of an unexpected runtime error by neatly packaging the use of a resource. There are two forms of the using statement. The first form is the following, and is illustrated in Figure 9-11. The code between the parentheses allocates the resource. The Statement is the code that uses the resource. The using statement implicitly generates the code to dispose of the resource. using ( ResourceType Identifier = Expression ) Statement Allocates resource Uses resource Unexpected runtime errors are called exceptions, and are covered in 11. The standard way of handling the possibility of exceptions is to place the code that might cause an exception in a try block, and place any code that must be executed, whether or not there is an exception, into a finally block. This form of the using statement does exactly that. It performs the following: Allocates the resource Places the Statement in a try block Creates a call to the resource s Dispose method and places it in a finally block.