Sqlite3 Example of Prepared Statements

makefile

.PHONY: all
all: test.cpp
	g++ test.cpp -lsqlite3

.PHONY: clean
clean:
	rm a.out

test.cpp

#include <cstdio>
#include <cstdlib>
#include <ctime>
#include <cmath>
#include <string>
#include <sqlite3.h>

sqlite3* db;

const char sql_tb[] = 
"CREATE TABLE FOO("
"ID  INTEGER PRIMARY KEY AUTOINCREMENT, "
"A   INTEGER, "
"B   TEXT, "
"C   REAL);";

const char sql_insert[] =
"INSERT INTO FOO(A, B, C) VALUES(?1, ?2, ?3);";

static int cb_table_make(void* notused, int argc, char** argv,
        char** azColNm){
    return 0;
}

static int cb(void* notused, int argc, char** argv, 
        char** azColNm){
    for(int i = 0; i < argc; i++){
        printf("%s = %s\n", azColNm[i], argv[0]);
    }
    return 0;
}
int main(){
    srand(time(0));
    char* zErrMsg;
    int   rc = sqlite3_open("a.sqlite", &db);
    if(rc){
        // handle error
        fprintf(stderr, "%s\n", sqlite3_errmsg(db));
    }
    
    // Creating A Table
    rc = sqlite3_exec(db, sql_tb, cb_table_make, 0, &zErrMsg);
    if(rc){
        printf("%s\n", zErrMsg);
        sqlite3_free(zErrMsg);
    }
    
    // Demo of Prepared Statements
    sqlite3_stmt* stmt;
    rc = sqlite3_prepare_v2(db, sql_insert, -1, &stmt, NULL);
    if(rc){
        puts("Failed to prepare statement\n");
    }
    for(int i = 0; i < 100; i++){
        std::string str;
        for(int n = 0; n < 10; n++){
            str += rand() % 96 + 32;
        }
        sqlite3_bind_int(stmt, 1, i * rand());
        sqlite3_bind_text(stmt, 2, str.c_str(), -1,
            SQLITE_STATIC);
        sqlite3_bind_double(stmt, 3, 
            (double)rand() / (double)rand());
        sqlite3_step(stmt);
    }
    sqlite3_finalize(stmt);

    // Select from the table
    rc = sqlite3_exec(db, "SELECT * FROM FOO;", cb, 0, &zErrMsg);
    if(rc){
        // error handling, print zErrMsg and free it
        printf("%s\n", zErrMsg);
        sqlite3_free(zErrMsg);
    }
    // close the database
    sqlite3_close(db);
}