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iOS 原生sqlite3的使用方法

2020-07-26 02:35:04
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本文介绍了iOS 原生sqlite3的使用方法,分享给大家,具体如下:

SQLite?

  1. SQLit是一个开源、轻型嵌入式关系数据库,诞生于2000年5月
  2. 占用资源非常的低,在嵌入式设备中,可能只需要几百K的内存就够了
  3. 能够支持Windows/Linux/Unix等等主流的操作系统
  4. 比起Mysql、PostgreSQL这两款开源的世界著名数据库管理系统来讲,它的处理速度比他们都快

 SQL语句常用操作

增、删、改、查,CRUD,Create[新建], Retrieve[检索], Update[更新], Delete[删除]。

SQL语法写法特点

1、不区分大小写(CREATE = create)
2、每条语句以分号(;)结尾
3、关键字建议大写

SQL语句常用关键字

select、insert、update、delete、from、create、where、desc、order、by、group、table、alter、view、index等

  1. 数据定义语句(DDL):包括create和drop等操作,在数据库中创建新表或删除表(create table或 drop table)
  2. 数据操作语句(DML):包括insert、update、delete等操作,分别用于添加、修改、删除表中的数据
  3. 数据查询语句(DQL):可以用于查询获得表中的数据,关键字select是DQL(也是所有SQL)用得最多的操作,其他DQL常用的关键字有where,order by,group by和having
// ViewController.m// sqlite3//// Created by 周玉 on 2017/12/13.// Copyright © 2017年 guidekj. All rights reserved.//#import "ViewController.h"#import <sqlite3.h>#define KUIScreenWidth [UIScreen mainScreen].bounds.size.width#define KUIScreenHeight [UIScreen mainScreen].bounds.size.height#define FILE_NAME @"saas.sqlite"static sqlite3 *db = nil;@interface ViewController ()@end@implementation ViewController- (void)viewDidLoad {  [super viewDidLoad];  self.title = @"sqlite3";  //DDB//  [self openDB];//  [self closeDB];  //DDL//  [self createTable];//  [self dropTable];  //DML//  [self insertData];//  [self updateData];//  [self deleteData];  //DQL  [self queryData];}#pragma mark 查询- (void)queryData{  sqlite3 *newDB = [self openDB];  sqlite3_stmt *statement = nil;  NSString *sqlStr = @"SELECT * FROM SAAS_PERSON";  int result = sqlite3_prepare_v2(newDB, sqlStr.UTF8String, -1, &statement, NULL);  if (result == SQLITE_OK) {    //遍历查询结果    if (!(sqlite3_step(statement) == SQLITE_DONE)) {      while (sqlite3_step(statement) == SQLITE_ROW) {        int ID = sqlite3_column_int(statement, 0);        const unsigned char *name = sqlite3_column_text(statement, 1);        const unsigned char *sex = sqlite3_column_text(statement, 2);        int age = sqlite3_column_int(statement, 3);        const unsigned char *description = sqlite3_column_text(statement, 4);        NSLog(@"ID = %d , name = %@ , sex = %@ , age = %d , description = %@",ID,[NSString stringWithUTF8String:(const char *)name],[NSString stringWithUTF8String:(const char *)sex],age,[NSString stringWithUTF8String:(const char *)description]);      }    } else {      NSLog(@"查询语句完成");    }  } else {    NSLog(@"查询语句不合法");  }  sqlite3_finalize(statement);  [self closeDB];}#pragma mark 删除数据记录- (void)deleteData{  sqlite3 *newDB = [self openDB];  sqlite3_stmt *statement = nil;  NSString *sqlStr = @"DELETE FROM SAAS_PERSON WHERE NAME = '王鹏飞'";  int result = sqlite3_prepare_v2(newDB, sqlStr.UTF8String, -1, &statement, NULL);  if (result == SQLITE_OK) {    if (sqlite3_step(statement) == SQLITE_DONE) {      NSLog(@"删除操作完成");    }  } else {    NSLog(@"删除操作不合法");  }  sqlite3_finalize(statement);  [self closeDB];}#pragma mark 更新数据记录- (void)updateData{  sqlite3 *newDB = [self openDB];  sqlite3_stmt *statement = nil;  NSString *sqlStr = @"UPDATE SAAS_PERSON SET DESCRIPTION = '喜欢运动,旅游' WHERE NAME = '周玉'";  int result = sqlite3_prepare_v2(newDB, sqlStr.UTF8String, -1, &statement, NULL);  if (result == SQLITE_OK) {    if (sqlite3_step(statement) == SQLITE_DONE) {      NSLog(@"更新信息完成");    }  } else {    //[logging] no such column: DESCRIPT (KEY拼写错误) --- 更新信息不合法    NSLog(@"更新信息不合法");  }  sqlite3_finalize(statement);  [self closeDB];}#pragma mark 新增数据记录- (void)insertData{  sqlite3 *newDB = [self openDB];  sqlite3_stmt *statement = nil;//  NSString *sqlStr = @"INSERT INTO SAAS_PERSON (NAME , SEX , AGE , DESCRIPTION) VALUES('周玉','男',28,'开朗乐观')";//  NSString *sqlStr = @"INSERT INTO SAAS_PERSON (NAME , SEX , AGE , DESCRIPTION) VALUES('王鹏飞','女',27,'开朗乐观')";//  NSString *sqlStr = @"INSERT INTO SAAS_PERSON (NAME , SEX , AGE , DESCRIPTION) VALUES('李梅','女',20,'年轻可爱��')";  NSString *sqlStr = @"INSERT INTO SAAS_PERSON (NAME , SEX , AGE , DESCRIPTION) VALUES('sumit','男',15,'小朋友的年纪')";  //检验合法性  int result = sqlite3_prepare_v2(newDB, sqlStr.UTF8String, -1, &statement, NULL);  if (result == SQLITE_OK) {    //判断语句执行完毕    if (sqlite3_step(statement) == SQLITE_DONE) {      NSLog(@"插入的信息完成");    }  } else {    NSLog(@"插入的信息不合法");  }  sqlite3_finalize(statement);  [self closeDB];}#pragma mark 创建表- (void)createTable{  sqlite3 *newDB = [self openDB];  //  char *sql = "CREATE TABLE IF NOT EXISTS t_person (ID INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, NAME TEXT , SEX TEXT,AGE INTEGER,DESCRIPTION TEXT);";  NSString *sqlStr = @"CREATE TABLE IF NOT EXISTS SAAS_PERSON (ID INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, NAME TEXT , SEX TEXT,AGE INTEGER,DESCRIPTION TEXT);";  char *error = NULL;  int result = sqlite3_exec(newDB, sqlStr.UTF8String, NULL, NULL, &error);  if (result == SQLITE_OK) {    NSLog(@"创建表成功");  } else {    NSLog(@"创建表失败 = %s",error);  }  [self closeDB];}#pragma mark 删除表- (void)dropTable{  sqlite3 *newDB = [self openDB];  NSString *sqlStr = @"DROP TABLE t_person";  char *error = NULL;  int result = sqlite3_exec(newDB, sqlStr.UTF8String, NULL, NULL, &error);  if (result == SQLITE_OK) {    NSLog(@"删除表成功");  } else {    NSLog(@"删除表失败 = %s",error);  }  [self closeDB];}#pragma mark 打开或者创建数据库- (sqlite3 *)openDB {  if (!db) {    //1.获取document文件夹的路径    //参数1:文件夹的名字 参数2:查找域 参数3:是否使用绝对路径    NSString *documentPath = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)[0];    //获取数据库文件的路径    NSString *dbPath = [documentPath stringByAppendingPathComponent:@"saas.sqlite"];    NSLog(@"%@",dbPath);    //判断document中是否有sqlite文件    int result = sqlite3_open([dbPath UTF8String], &db);    if (result == SQLITE_OK) {      NSLog(@"打开数据库");    }else{      [self closeDB];      NSLog(@"打开数据库失败");    }  }  return db;}#pragma mark 关闭数据库- (void)closeDB{  int result = sqlite3_close(db);  if (result == SQLITE_OK) {    NSLog(@"数据库关闭成功");    db = nil;  } else {    NSLog(@"数据库关闭失败");  }}@end

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