112 lines
4.4 KiB
C++
112 lines
4.4 KiB
C++
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/**
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* Got it from here https://www.tutlane.com/tutorial/sqlite/sqlite-case-statement
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*/
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#include <sqlite_orm/sqlite_orm.h>
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#include <iostream>
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using namespace sqlite_orm;
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using std::cout;
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using std::endl;
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int main() {
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struct Student {
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int id = 0;
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std::string name;
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std::string email;
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float marks = 0;
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#ifndef SQLITE_ORM_AGGREGATE_NSDMI_SUPPORTED
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Student() {}
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Student(int id, std::string name, std::string email, float marks) :
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id{id}, name{std::move(name)}, email{std::move(email)}, marks{marks} {}
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#endif
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};
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auto storage = make_storage({},
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make_table("STUDENT",
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make_column("ID", &Student::id, primary_key()),
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make_column("NAME", &Student::name),
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make_column("EMAIL", &Student::email),
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make_column("MARKS", &Student::marks)));
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storage.sync_schema();
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storage.transaction([&storage] {
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storage.replace(Student{1, "Shweta", "shweta@gmail.com", 80});
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storage.replace(Student{2, "Yamini", "rani@gmail.com", 60});
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storage.replace(Student{3, "Sonal", "sonal@gmail.com", 50});
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storage.replace(Student{4, "Jagruti", "jagu@gmail.com", 30});
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return true;
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});
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// list all students
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for(auto& student: storage.iterate<Student>()) {
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cout << storage.dump(student) << endl;
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}
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cout << endl;
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{ // without alias
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// SELECT ID, NAME, MARKS,
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// CASE
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// WHEN MARKS >=80 THEN 'A+'
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// WHEN MARKS >=70 THEN 'A'
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// WHEN MARKS >=60 THEN 'B'
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// WHEN MARKS >=50 THEN 'C'
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// ELSE 'Sorry!! Failed'
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// END
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// FROM STUDENT;
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auto rows = storage.select(columns(&Student::id,
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&Student::name,
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&Student::marks,
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case_<std::string>()
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.when(greater_or_equal(&Student::marks, 80), then("A+"))
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.when(greater_or_equal(&Student::marks, 70), then("A"))
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.when(greater_or_equal(&Student::marks, 60), then("B"))
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.when(greater_or_equal(&Student::marks, 50), then("C"))
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.else_("Sorry!! Failed")
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.end()));
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for(auto& row: rows) {
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cout << std::get<0>(row) << ' ' << std::get<1>(row) << ' ' << std::get<2>(row) << ' ' << std::get<3>(row)
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<< endl;
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}
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cout << endl;
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}
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{ // with alias
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struct GradeAlias : alias_tag {
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static const std::string& get() {
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static const std::string res = "Grade";
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return res;
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}
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};
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// SELECT ID, NAME, MARKS,
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// CASE
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// WHEN MARKS >=80 THEN 'A+'
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// WHEN MARKS >=70 THEN 'A'
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// WHEN MARKS >=60 THEN 'B'
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// WHEN MARKS >=50 THEN 'C'
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// ELSE 'Sorry!! Failed'
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// END as 'Grade'
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// FROM STUDENT;
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auto rows = storage.select(columns(&Student::id,
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&Student::name,
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&Student::marks,
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as<GradeAlias>(case_<std::string>()
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.when(greater_or_equal(&Student::marks, 80), then("A+"))
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.when(greater_or_equal(&Student::marks, 70), then("A"))
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.when(greater_or_equal(&Student::marks, 60), then("B"))
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.when(greater_or_equal(&Student::marks, 50), then("C"))
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.else_("Sorry!! Failed")
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.end())));
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for(auto& row: rows) {
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cout << std::get<0>(row) << ' ' << std::get<1>(row) << ' ' << std::get<2>(row) << ' ' << std::get<3>(row)
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<< endl;
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}
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cout << endl;
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}
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return 0;
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}
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