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Reference Guide
SQLiteVersionsOfRoot.C File Reference

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This tutorial demonstrates how TSQLServer can be used to create a connection with a SQlite3 database. It accesses the Sqlite data base. Download from https://root.cern/files/root_download_stats.sqlite Then a TH1F histogram is created and filled using a expression which receives the recorded values in the "version" column of the sqlite3 database. The histogram shows the usage of the ROOT development version. This product includes GeoLite2 data created by MaxMind, available from http://www.maxmind.com.

#include <TSQLiteServer.h>
#include <TSQLiteResult.h>
#include <TSQLRow.h>
#include <TString.h>
void SQLiteVersionsOfRoot(){
TSQLServer *db = TSQLServer::Connect("sqlite://root_download_stats.sqlite", "", "");
const char *rootSourceVersion = "SELECT Version FROM accesslog;";
TSQLResult *rootSourceVersionRes = db->Query(rootSourceVersion);
TH1F *hVersionOfRoot= new TH1F("hVersionOfRoot", "Development Versions of ROOT", 7, 0, -1);
while (TSQLRow *row = rootSourceVersionRes->Next()) {
TString rowVersion(row->GetField(0));
TString shortVersion(rowVersion(0,4));
hVersionOfRoot->Fill(shortVersion,1);
delete row;
}
TCanvas *VersionOfRootHistogram = new TCanvas();
hVersionOfRoot->GetXaxis()->LabelsOption("a");
hVersionOfRoot->LabelsDeflate("X");
hVersionOfRoot->Draw();
}
virtual void LabelsOption(Option_t *option="h")
Set option(s) to draw axis with labels option can be:
Definition: TAxis.cxx:641
The Canvas class.
Definition: TCanvas.h:23
1-D histogram with a float per channel (see TH1 documentation)}
Definition: TH1.h:574
TAxis * GetXaxis()
Definition: TH1.h:319
virtual Int_t Fill(Double_t x)
Increment bin with abscissa X by 1.
Definition: TH1.cxx:3338
void Draw(Option_t *option="") override
Draw this histogram with options.
Definition: TH1.cxx:3060
virtual void LabelsDeflate(Option_t *axis="X")
Reduce the number of bins for the axis passed in the option to the number of bins having a label.
Definition: TH1.cxx:5209
virtual TSQLRow * Next()=0
virtual TSQLResult * Query(const char *sql)=0
static TSQLServer * Connect(const char *db, const char *uid, const char *pw)
The db should be of the form: <dbms>://<host>[:<port>][/<database>], e.g.: mysql://pcroot....
Definition: TSQLServer.cxx:61
Basic string class.
Definition: TString.h:136
Author
Alexandra-Maria Dobrescu 08/2018

Definition in file SQLiteVersionsOfRoot.C.