SQLite使用(一)

简单介绍SQLite常用API:

int sqlite3_open(
  const char *filename,   /* Database filename (UTF-8) */
  sqlite3 **ppDb          /* OUT: SQLite db handle */
);

int sqlite3_close(sqlite3*);

int sqlite3_exec(
  sqlite3*,                                  /* An open database */
  const char *sql,                           /* SQL to be evaluated */
  int (*callback)(void*,int,char**,char**),  /* Callback function */
  void *,                                    /* 1st argument to callback */
  char **errmsg                              /* Error msg written here */
);

一个小DEMO： 

#include <stdio.h>
#include <sqlite3.h>

static int callback(void *NotUsed, int argc, char **argv, char **azColName) {
    for (int i = 0; i < argc; i++) {
        printf("%s = %s
", azColName[i], argv[i] ? argv[i]: "NULL");
    }
    printf("
");
    return 0;
}

int main(int argc, char **argv)
{
    sqlite3 *db;
    int rc;
    
    rc = sqlite3_open("test.db", &db);
    
    if (rc) {
        printf("Can't open database: %s
", sqlite3_errmsg(db));
        sqlite3_close(db);
        return 1;
    } else {
        printf("Open database successfully
");
    }
    
    char *sql;
    char *zErrMsg = 0;
    
    /* Create SQL statement */
    sql = "CREATE TABLE COMPANY("  
    "ID INT PRIMARY KEY     NOT NULL," 
    "NAME           TEXT    NOT NULL," 
    "AGE            INT     NOT NULL," 
    "ADDRESS        CHAR(50)," 
    "SALARY         REAL );";
    
    rc = sqlite3_exec(db, sql, callback, 0, &zErrMsg);
    if (rc != SQLITE_OK) {
        printf("SQL error: %s
", zErrMsg);
        sqlite3_free(zErrMsg);
    } else {
        printf("Create table successfully
");
    }
    
    sql = "INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY) "  
    "VALUES (1, 'Paul', 32, 'California', 20000.00 ); " 
    "INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY) "  
    "VALUES (2, 'Allen', 25, 'Texas', 15000.00 ); "     
    "INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY)" 
    "VALUES (3, 'Teddy', 23, 'Norway', 20000.00 );" 
    "INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY)" 
    "VALUES (4, 'Mark', 25, 'Rich-Mond ', 65000.00 );";
    
    rc = sqlite3_exec(db, sql, callback, 0, &zErrMsg);
    if (rc != SQLITE_OK) {
        printf("SQL error: %s
", zErrMsg);
        sqlite3_free(zErrMsg);
    } else {
        printf("Insert Table successfully
");
    }
    
    sql = "SELECT * from COMPANY";
    
    rc = sqlite3_exec(db, sql, callback, 0, &zErrMsg);
    if (rc != SQLITE_OK) {
        printf("SQL error: %s
", zErrMsg);
        sqlite3_free(zErrMsg);
    }

    sqlite3_close(db);
    return 0;
}