Database Wrapper - bibliothèque pour MetaTrader 5

Introduction

This is an encapsulation library of DatabaseXXX series functions, which realizes the automatic release of resources

//Open

CDatabase db( "test.db" );   //对象生命周期结束时，自动调用DatabaseClose

Print ( "db IsAvaliable=" , db.IsAvaliable());

// have table

 Print ( "table" ,db.HasTable( "tab" ) ? "exist" : "不存在" );

//implement

db.Execute("创建表tab(aa integer, bb double , cc string );");

for ( int i= 1 ;i< 10 ;i++)
{

db.Execute( StringFormat ("插入 (aa, bb, cc) 值(%d, %G, %s);", i, rand ()/ 100 , SQLiteTimeStr( TimeCurrent ())));

}

//read

CDatabaseRequest req = db.Query( "select * from tab" ); //对象生命周期结束时，自动调用DatabaseFinalize

int v;

req.GetInteger( 0 , v);

int v2 = req.GetIntegerOrDefault( "aa" );

 int v;

double d;

string  s;

bool rc = db.QueryFirst< int , double , string >(v, d, s, "select * from tab" );

 int v[];

double d[];

string s[];

bool rc = db.Query< int , double , string >(v, d, s, "select * from tab" );