|
|
 |
|
|
|
|
Establishing the environment by allocating a database connection handle (hDbc) using ODBC's SQLAllocConnect. You also need a valid data source name (DSN), user ID, and password for databases that require them. |
|
|
|
|
|
|
|
|
Establishing the environment by allocating a SQL/database command statement handle (hStmt). |
|
|
|
|
|
|
|
|
Working with the actual data by binding columns, opening and closing cursors, and moving through sets of records. |
|
|
|
|
|
|
|
|
Deallocating a SQL/database command statement handle (hStmt). |
|
|
|
|
|
|
|
|
Deallocating a database connection handle (hDbc). |
|
|
|
|
|
|
|
|
Deallocating an environment handle (hEnv). |
|
|
|
|
|
|
|
|
7. What are the advantages and disadvantages of using Data controls? |
|
|
|
|
|
|
|
|
The advantages include ease of implementation, ease of maintenance when data access is relatively straightforward, and rapid development. Disadvantages include susceptibility to data control failure, less code reuse, and less ease of code duplication. |
|
|
|
|
|
|
|
|
1. What is the compartmental hierarchy for subsystems and their members? |
|
|
|
|
|
|
|
|
Subsystems are compartmentalized into classes. Classes are compartmentalized into methods, properties, and events. Subsystem compartments communicate with one another through a common interface. |
|
|
|
|
|
|
|
|
2. Why are subsystem interface classes so important? |
|
|
|
|
|
|
|
|
Subsystem interface classes are important because changes to them can cause a debugging and maintenance nightmare. |
|
|
|
|
|
|
|
|
3. What is a good way to decouple an actual form in the Graphical User Interface Subsystem from direct communications with the Database Access Subsystem? |
|
|
|
|
|
|
|
|
By using form controller classes, business or domain classes, and data access (or persistence) classes. |
|
|
|
|
|
|
|
|
4. What's the importance of collections of business classes in the Business Rules Subsystem? |
|
|
|
|
|
|
|
|
Often, applications deal with several records at a time, for which collections of business classes are useful. Business class collections are, in a sense, queues or stores of data out of which form controllers request information to display. Collections can very well be seen as mini-object-oriented databases that help shield (or encapsulate) the rest of the application from the relational database. |
|
|
|
|
|