87 lines
1.9 KiB
Markdown
87 lines
1.9 KiB
Markdown
# query_context
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A fluent sql query_context builder
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Object definition
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```cpp
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enum class Color {
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Red, Green, Blue, Yellow, Pink, Black, White
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};
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struct Coordinate
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{
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int x;
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int y;
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int z;
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};
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// special handling for custom type Coordinate
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namespace matador::utils::access {
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template<class Operator>
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void attribute(Operator &op, const char *id, Coordinate &value, const field_attributes &attr = null_attributes) {
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attribute(op, (std::string(id) + "_x").c_str(), value.x, attr);
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attribute(op, (std::string(id) + "_y").c_str(), value.y, attr);
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attribute(op, (std::string(id) + "_z").c_str(), value.z, attr);
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}
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}
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struct airplane
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{
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unsigned long id;
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std::string brand;
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std::string model;
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Color color;
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Coordinate position;
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template<class Operator>
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void process(Operator &op) {
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namespace field = matador::utils::access;
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field::primary_key(op, "id", id);
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field::attribute(op, "brand", brand, 255);
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field::attribute(op, "model", model, 255);
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field::attribute(op, "color", color);
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field::attribute(op, "position", position);
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}
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};
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```
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```cpp
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connection_pool<connection> pool("sqlite://sqlite.db", 4);
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session s(pool);
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// create all tables
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s.create().table<airplane>().execute();
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std::vector<entity<airplane>> planes {
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make_entity<airplane>(1, "Airbus", "A380"),
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make_entity<airplane>(2, "Boeing", "707"),
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make_entity<airplane>(3, "Boeing", "747")
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};
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auto stmt = s.insert()
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.into<airplane>("airplane")
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.values<airplane>().prepare();
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// insert
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for (const auto &plane: planes) {
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auto res = stmt.bind(*plane).execute();
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stmt.reset();
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}
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s.update("airplane")
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.set({"model", "737"})
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.where("id"_col == 2)
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.execute();
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auto result = s.select<airplane>()
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.from("airplane")
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.where("brand"_col == "Boeing")
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.execute();
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for (const auto &plane : result) {
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std::cout << "airplane: " << plane->brand << " - " << plane->model << "\n";
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}
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``` |