ORM_MYSQL

Mysql ORM (Object Relation Mapping)

a C++ Orm for mysql

☺️steal many many ideas and codes from this cool man's sqlite orm, you also can go there and find his blog for explanation of sqlite orm.

1 Preparation

well,firstly you should have installed your mysql.

1.1 Install C connector for mysql

You can install it from official website

1.2 Add and Include orm_mysql.h with your source files

1.3 Add compile option "-lmysqlclient"

if you use makefile tool or gcc,just add it. Or if you are in windows by vs, you should include a dynamic library called "mysqlclient.lib" (I guess it's called that.....:no_mouth:)

in Qt, you should add "QMAKE_LIBS+= -lmysqlclient" in your pro file.

2 Use it

2.1 Connect your database

firstly,you should add

using namespace ORM_MYSQL_THIEF;

and then you should add some codes at your class, just like this:

// add this line 
using namespace ORM_MYSQL_THIEF;

class MyClass
{

// this line are critical, first "serverDB" is your table name, first "id" will be your primary key if you don't want to pass another primary key.
// And id ... score are column fields that you want to add to your database
ORMAP_MYSQL(serverDB,id,name,level,score)

public:

MyClass(std::string idr,std::string namer,int levels,float score)
            :id(idr),name(namer),level(levels),score(score)
    {}

    std::string id;
    std::string name;
    int level;
    float score;
};

Then you can connect your mysql by just a line code:

 ORMapper mapper("localhost","username","password","database",port);

2.2 create,delete,insert,update,query,count

This orm (:laughing: i think i can say it's called that...) just implements few operations and if you are interested in it, you can change it.

/////////// You can create your class like this.
 std::vector<MyClass> listClassObject;
    MyClass helper("000","yyy",0,0);
    MyClass wodner1("111","thief",999,56.4);
    MyClass wodner2("222","fly",88,54.2);
    MyClass wodner3("333","universe",5,45.9);
    MyClass wodner4("444","keybord",34,99.9);

    listClassObject.push_back(wodner1);
    listClassObject.push_back(wodner2);
    listClassObject.push_back(wodner3);
    listClassObject.push_back(wodner4);

////////// Then you can _DO_ :
    /* create */
    mapper.createTbl(helper);   //create a table by info in wodner1
//      | id | name | level | score |

    mapper.createTbl(wodner1,1,"number");  // add a "auto_increment" field "number" to your table
//      | id | name | level | score | number |   

    /* insert  classObject */
    mapper.insert(wodner1);   // insert one 
    mapper.insertRange(listClassObject);   // insert a vector
        
    /* delete */
    mapper.dropTbl(helper);     //delete table
    mapper.deleteRow(wodner1);  //delete a row
    
    /* update */
    mapper.update(wodner1);     // update one 
    mapper.updateRange(listClassObject); //update a vector
    
    /* select and query */
    mapper.select(helper,Exp("name,id")).toVector();  //select name,id 
    mapper.select(helper).toVector();
        
    auto resultA=mapper.select(helper) 
                      .query()
                      .where(Exp("level")<78)
                      .toVector();
                      
    auto resultB=mapper.query(helper)      // no select, will select *
                     .where(Exp("level")<90)       // also .where(Exp("name")=="thief")
                     .limit(2)          // we also can have a "limit" and "offset" operation
                     .offset(0)
                     .toVector();
// when you want to create a table, select or query, you need to pass a "helper" classObject.
// you can find we can use Exp to wrap your fields names, then we can create select fields (like "name,id")
//where (like "level")for querying.

// query and select will get a two-dimensional vector whose structure you can get value like this:
     for(auto h:resultB)
     {
     // resultB is a two-dimensional vector, h is a vector
     // now h[0] is a string for "id", h[1] is a string for "name", h[2] is a int for "level", h[3] is a float for "score"
        MyClass lol(h[0],h[1],h[2],h[3]);
        lol.printItself();
     }
        
     /* count */
     int counter=mapper.query(helper).where(Exp("level")<88).count(); // return a number for your query

    

3 welcome to improve it~

😆 Some other funtions in mysql are not implemented (like null value, multiple tables operations and etc....😆).Hope that you can improve it if you like it. I also believe my comment can help you understand these codes.If you have questions you can create a issue.