本文整理汇总了C++中database::select方法的典型用法代码示例。如果您正苦于以下问题：C++ database::select方法的具体用法？C++ database::select怎么用？C++ database::select使用的例子？那么恭喜您, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类database的用法示例。
在下文中一共展示了database::select方法的1个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的C++代码示例。
示例1: find_all_janitors
void find_all_janitors(database My_DB){
//In this function all janitors are retreived.
//This is done by first finding the department
//object with "Janitors" as value in to the
//Name attribute
ODB_QSTREAM q_stream;
ODB_SSTREAM s_stream;
ODB_REF o,jo;
char typenm[16]="Department";
char propnm[8]="Name";
char val[16]="Janitors";
//Open a stream over the department type with the condition that
//the Name attribute must have Janitors as value
q_stream=My_DB.open_stream(typenm,propnm,val);
//The stream may not be opened if so it is best to check before use.
if (q_stream==NULL) {
cout<<"\nError when opening stream bla bla bla...\n";
return;
};
//The stream was opened allright. In the remaining we only consider the
//first found department named Janitors, thus we do not assume the name
//to be a key to departments
o=My_DB.get(q_stream);
//If o==NULL yhen there were no such department in the database
if (o==NULL) {
cout<<"No department named "<<val<<" exist in the database\n";
return;
}
//No longer req'd
My_DB.close_stream(q_stream);
//reuse q_stream to open the stream to select all employees at
//the department bound to object reference o
q_stream=My_DB.open_stream("Employee","EmployedAt",o);
if (q_stream==NULL) {
cout<<"\nError when opening stream over employee\n";
return;
};
cout<<"\nThese are the Janitors\n-------------------------\n";
obuf.reset_buffer(); //reset the buffer
//Now, we can start browsing the janitors
jo=My_DB.get(q_stream);
while (jo!=NULL){
jo->display(obuf);
cout<<obuf.get_buffer()<<'\n';
obuf.reset_buffer();
jo=My_DB.get(q_stream);
};
//Now, Lets select those janitors who earn more than 10000.
//This is accomplished by opening a select stream over the
//query stream which selects all janitors.
//First, reset the stream
My_DB.reset_stream(q_stream);
//secondly, open a select stream over q_stream with the
//condition that the salary should be greater than 10000
s_stream=My_DB.select(q_stream,"Salary",">",(ODB_INT)10000);
cout<<"\n Theese are all the rich janitors\n";
obuf.reset_buffer(); //reset the buffer
//Now, we can start browsing the rich janitors
jo=My_DB.get(s_stream);
while (jo!=NULL){
jo->display(obuf);
cout<<obuf.get_buffer()<<'\n';
obuf.reset_buffer();
jo=My_DB.get(s_stream);
};
My_DB.close_stream(s_stream);
}