linux下使用c++操作sqlite数据库

825人浏览 2024-04-12 22:32:27

背景

公司主要做人工智能相关，包括基于机器视觉方向的图像识别，现需要做一款基于边缘计算设备的产品，需要用到sqlite数据库，下面记录一下安装过程和简单语法。

安装sqlite相关库

设备信息：ubuntu18.x系统，arm处理器，4G内存...

1.1 下载sqlite源码

下载sqlite源码

也可进入官网手动下载，注意下载名称为“sqlite-autoconf”类型的压缩包。

1.2 解压缩包

解压到当前目录：tar -zxvf
sqlite-autoconf-3410000.tar.gz

进入解压目录：cd sqlite-autoconf-3410000

1.3 链接/编译

执行命令前需进入root模式，然后执行以下命令

./configure

make install

等待编译完成。

测试/sqlite简单使用

2.1 重要API介绍

sqlite3_open(const char *filename, sqlite3 **ppDb)

作用：打开一个指向 SQLite 数据库的连接，返回一个用于其他 SQLite 操作的数据库连接对象。

sqlite3_exec(sqlite3*, const char *sql, sqlite_callback, void *data, char **errmsg)
作用：提供了一个执行 SQL 命令的快捷方式，SQL 命令由 sql 参数提供，可以由多个 SQL 命令组成。

int sqlite3_exec(
       sqlite3*,                                  /* 上述sqlite3_open函数打开的db对象*/
       const char *sql,                           /* sql语句 */
       int (*callback)(void*,int,char**,char**),  /* 回调函数 */
       void *data,                                    /* 回调函数的第一个参数 */
       char **errmsg                              /* 异常/异常信息 */
    );

sqlite3_close(sqlite3*)

作用：关闭之前sqlite3_open() 打开的数据库连接。

2.2 简单语法介绍

连接/打开数据库并创建数据库表

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

static int callback(void *NotUsed, int argc, char **argv, char **azColName){
    int i;
    for(i=0; i<argc; i++){
      printf("%s = %s\n", azColName[i], argv[i] ? argv[i] : "NULL");
    }
    printf("\n");
    return 0;
  }
  
  int main(int argc, char **argv){
    sqlite3 *db;
    char *zErrMsg = 0;
    int rc;
    char* sql;
    const char* data = "Callback function called";

    rc = sqlite3_open("myDemo.db", &db);
    if( rc ){//打开数据库失败
      fprintf(stderr, "Can't open database: %s\n", sqlite3_errmsg(db));
      sqlite3_close(db);
      return(1);
    }
    //创建sql语句
    sql = "CREATE TABLE COMPANY("  \
            "ID INT PRIMARY KEY     NOT NULL," \
            "NAME           TEXT    NOT NULL," \
            "AGE            INT     NOT NULL," \
            "ADDRESS        CHAR(50)," \
            "SALARY         REAL );";

    /* 执行sql */
    rc = sqlite3_exec(db, sql, callback, 0, &zErrMsg);
    if( rc != SQLITE_OK ){
    fprintf(stderr, "SQL error（create）: %s\n", zErrMsg);
        sqlite3_free(zErrMsg);
    }else{
        fprintf(stdout, "Table created successfully\n");
    }
		sqlite3_close(db);
    return 0；
  }

插入操作

   /* 插入sql语句 */
    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 );";

    /* Execute SQL statement */
    rc = sqlite3_exec(db, sql, callback, 0, &zErrMsg);
    if( rc != SQLITE_OK ){
        fprintf(stderr, "SQL error（insert）: %s\n", zErrMsg);
        sqlite3_free(zErrMsg);
    }else{
        fprintf(stdout, "Records created successfully\n");
    }

查询操作

    /* 查询sql语句 */
    sql = "SELECT * from COMPANY";

    /* Execute SQL statement */
    rc = sqlite3_exec(db, sql, callback, (void*)data, &zErrMsg);
    if( rc != SQLITE_OK ){
        fprintf(stderr, "SQL error（select）: %s\n", zErrMsg);
        sqlite3_free(zErrMsg);
    }else{
        fprintf(stdout, "Operation(select) done successfully\n");
    }

更新操作

    /* 更新sql语句 */
    sql = "UPDATE COMPANY set SALARY = 25000.00 where ID=1; " \
            "SELECT * from COMPANY";

    /* Execute SQL statement */
    rc = sqlite3_exec(db, sql, callback, (void*)data, &zErrMsg);
    if( rc != SQLITE_OK ){
        fprintf(stderr, "SQL error（update）: %s\n", zErrMsg);
        sqlite3_free(zErrMsg);
    }else{
        fprintf(stdout, "Operation(update) done successfully\n");
    }

删除操作

    /* 删除sql语句 */
    sql = "DELETE from COMPANY where ID=2; " \
            "SELECT * from COMPANY";

    /* Execute SQL statement */
    rc = sqlite3_exec(db, sql, callback, (void*)data, &zErrMsg);
    if( rc != SQLITE_OK ){
        fprintf(stderr, "SQL error（delete）: %s\n", zErrMsg);
        sqlite3_free(zErrMsg);
    }else{
        fprintf(stdout, "Operation(delete) done successfully\n");
    }