IOS 数据库管理系统(SQLite)

嵌入式数据库

SQLite嵌入式数据库的优势

1.支持事件,你并不需要配置,无需安装,不需要管理员

2.支持部分脂肪SQL92

3.完整的数据库被存储在磁盘上的文件的顶部,相同的数据库文件可以在不同机器上面使用,最大支持数据库2T

4.整个系统少于3万行,少于250KB的内存占用

Linux系统级的SQLite技术实现框架libsqlite3.0.dylib

開始使用SQLite

1.引入<sqlite3.h>头文件

2.打开数据库

3.运行SQL命令

4.关闭数据库

一下代码展示整个数据库的 打开,关闭,添加,删除,查找,改动,

创建一个单例

#import <Foundation/Foundation.h>
@class Student;
@interface DataBaseHandle : NSObject
//创建一个单例
+(DataBaseHandle *)shareDB;

//获取Documents路径
- (NSString *)documentsPath;

//打开数据库
- (void)openDB;

//关闭数据库
- (void)closeDB;

//创建表
- (void)createTable;

//插入信息
- (void)insertStudent:(Student *)stu;

//改动信息
- (void)updateMessage;

//删除信息
- (void)deleteMessage;

//查找所有
- (void)selectAllStudent;

//条件查找
- (void)selectWithSex:(NSString *)sex;

@end

#import "DataBaseHandle.h"
#import <sqlite3.h>
#import "Student.h"
//全局单利对象
static DataBaseHandle *shareModle = nil;
@implementation DataBaseHandle
#pragma mark 实现单利
+ (DataBaseHandle *)shareDB
{
    if (nil == shareModle)
    {
        shareModle = [[DataBaseHandle alloc] init];
    }
    return shareModle;
}

#pragma  mark 获取Documents路径
- (NSString *)documentsPath
{
    NSString *documentPath = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)[0];
    return documentPath;
}

//在操作数据之前引入框架(sql...3.0)
//声明一个数据库的对象
static sqlite3 *db = nil;
#pragma mark 打开数据库
- (void)openDB
{
    //推断数据库是不是为空
    if (nil == db)
    {
        //与documents路径拼接数据库存放路径(获得存放路径)
        NSString *dbPath = [[self documentsPath] stringByAppendingString:@"/Student.sqlite"];
        //依据路径打开数据库,如该路径下没有数据库,就自己主动创建一个数据库
        //打开数据库(c语言中的语法)
        int result = sqlite3_open(dbPath.UTF8String, &db);
        //推断是否打开数据库成功
        if (result == SQLITE_OK)
        {
            NSLog(@"数据库打开成功");
        }
        else
        {
            NSLog(@"数据库打开失败");
        }
    }
}

#pragma mark 关闭数据库

- (void)closeDB
{
    int result = sqlite3_close(db);
    if (result == SQLITE_OK)
    {
        //假设关闭成功,置为nill
        db = nil;
        NSLog(@"数据库关闭成功");
    }
    else
    {
        NSLog(@"数据库关闭失败");
    }
}

#pragma mark 创建表
- (void)createTable
{
    //要创建表,就要使用SQL语句.
    //SQL语句在这是以字符串的形式存在的
    NSString *createString = @"CREATE  TABLE  IF NOT EXISTS student (sid INTEGER PRIMARY KEY  AUTOINCREMENT  NOT NULL , sname TEXT, ssex TEXT, sage TEXT)";
    //运行SQL语句
   int result = sqlite3_exec(db, createString.UTF8String, NULL, NULL, NULL);

    if (result == SQLITE_OK)
    {
        NSLog(@"创建表成功");
    }
    else
    {
        NSLog(@"创建失败");
    }

}

#pragma mark 插入信息
- (void)insertStudent:(Student *)stu
{
    //准备插入语句
    NSString *insertString = [NSString stringWithFormat:@"INSERT INTO student (sname,ssex,sage) VALUES ('%@','%@','%@')",stu.name,stu.sex,stu.age];
    //运行语句
    int result = sqlite3_exec(db, insertString.UTF8String, NULL, NULL, NULL);
    if (result == SQLITE_OK)
    {
        NSLog(@"插入成功");
    }
    else
    {
        NSLog(@"插入失败");
    }

}

#pragma mark 改动数据
- (void)updateMessage
{
    //准备改动语句
    NSString *undataString = @"UPDATE student SET ssex = '女' ,sname = '小梦' WHERE  sid = 10";
    int result = sqlite3_exec(db, undataString.UTF8String, NULL, NULL, NULL);
    if (result == SQLITE_OK)
    {
        NSLog(@"改动成功");
    }
    else
    {
        NSLog(@"改动失败");
    }

}

#pragma  mark 删除数据
- (void)deleteMessage
{
    //准备删除语句
    NSString *deleteString = @"DELETE  FROM student WHERE sid = 1";
    int result = sqlite3_exec(db, deleteString.UTF8String, NULL, NULL, NULL);
    if (result == SQLITE_OK)
    {
        NSLog(@"delete OK");
    }
    else
    {
        NSLog(@"delete _NO");
    }

}

#pragma mark 查找所有
- (void)selectAllStudent
{
    //准备查找语句
    NSString *selectAll = @"SELECT *FROM student";
    //创建伴随指针
    sqlite3_stmt *stmt = nil;

    //预备运行
    int result = sqlite3_prepare(db, selectAll.UTF8String, -1, &stmt, NULL);
    if (result == SQLITE_OK)
    {
        //在没有查找完毕之前一直循环运行
        while (sqlite3_step(stmt) == SQLITE_ROW)
        {
            //取出sid(第0列)
            NSInteger sid = sqlite3_column_int(stmt, 0);
            //取出sname(第1列)
            NSString *sname = [NSString stringWithUTF8String:(const char *)sqlite3_column_text(stmt, 1)];
            //取出ssex(第2列)
            NSString *ssex = [NSString stringWithUTF8String:(const char *)sqlite3_column_text(stmt, 2)];
            //取出sage(第3列)
            NSString *sage = [NSString stringWithUTF8String:(const char *)sqlite3_column_text(stmt, 3)];
            NSLog(@"sid:%d sname:%@ ssex:%@ sage:%@",sid,sname,ssex,sage);

        }
        sqlite3_finalize(stmt);
    }
    else
    {
        //假设查找失败,结束伴随指针
        sqlite3_finalize(stmt);
        NSLog(@"查找失败");
    }

}
#pragma mark 条件查找
- (void)selectWithSex:(NSString *)sex
{
    //准备查找语句
    NSString *selecstString = @"SELECT * FROM student WHERE ssex = ?

";
    //创建伴随指针
    sqlite3_stmt *stmt = nil;
    //预运行
     int result = sqlite3_prepare(db, selecstString.UTF8String, -1, &stmt, NULL);

    if (result == SQLITE_OK)
    {
        //绑定?的值
        //"1"代表第一个问号"?

"和哪个參数绑定
        sqlite3_bind_text(stmt, 1, sex.UTF8String, -1, NULL);
        while (sqlite3_step(stmt) == SQLITE_ROW)
        {

            NSInteger sid = sqlite3_column_int(stmt, 0);
            NSString *sname = [NSString stringWithUTF8String:(const char *)sqlite3_column_text(stmt, 1)];
            NSString *ssex = [NSString stringWithUTF8String:(const char *)sqlite3_column_text(stmt, 2)];
            NSString *sage = [NSString stringWithUTF8String:(const char *)sqlite3_column_text(stmt, 3)];
            NSLog(@"sid: %d sname: %@ ssex: %@ sage: %@",sid,sname,ssex,sage);

        }

    }
    else
    {
        //关闭指针
        sqlite3_finalize(stmt);
        NSLog(@"查询失败");
    }
}

@end

创建一个Student类

#import <Foundation/Foundation.h>

@interface Student : NSObject
@property(nonatomic,strong)NSString *name;
@property(nonatomic,strong)NSString *age;
@property(nonatomic,strong)NSString *sex;
@end

在 ViewController.m中 ViewDidLoad 调用方法

    //打印路径
    NSLog(@"%@",[[DataBaseHandle shareDB] documentsPath]);
    //打开数据库
    [[DataBaseHandle shareDB] openDB];
    //创建表
    [[DataBaseHandle shareDB] createTable];

    //插入信息
//    Student *stu = [[Student alloc] init];
//    stu.name = @"小露";
//    stu.age = @"29";
//    stu.sex = @"女";
//    [[DataBaseHandle shareDB] insertStudent:stu];
    //改动
//    [[DataBaseHandle shareDB] updateMessage];
    //删除
//    [[DataBaseHandle shareDB] deleteMessage];
    //查找所有信息
//    [[DataBaseHandle shareDB] selectAllStudent];
    //依据条件查找信息
    [[DataBaseHandle shareDB] selectWithSex:@"女"];

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