1 //
  2 //  ViewController.m
  3 //  SQLite3的运用
  4 //
  5 //  Created by PengYunjing on 16/9/24.
  6 //  Copyright © 2016年 PYJ. All rights reserved.
  7 //
  8 
  9 /**
 10  *  说明：
 11  *  sqlite3           *ppDb, 数据库句柄，跟文件句柄FILE很类似
 12  *  sqlite3_stmt      *stmt, 这个相当于ODBC的Command对象，用于保存编译好的SQL语句
 13  *  sqlite3_open(),   打开数据库，没有数据库时创建。
 14  *  sqlite3_exec(),   执行非查询的sql语句
 15  *  sqlite3_step(),   在调用sqlite3_prepare后，使用这个函数在记录集中移动。
 16  *  sqlite3_close(),  关闭数据库文件
 17  *
 18  *  还有一系列的函数，用于从记录集字段中获取数据，如
 19  *  sqlite3_column_text(), 取text类型的数据。
 20  *  sqlite3_column_blob(), 取blob类型的数据
 21  *  sqlite3_column_int(),  取int类型的数据
 22  */
 23 
 24 #import "ViewController.h"
 25 #import <sqlite3.h>
 26 
 27 //设置数据库的路径
 28 #define FileName [[NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:@"personinfo.sqlite"]
 29 
 30 @interface ViewController ()
 31 
 32 @end
 33 
 34 @implementation ViewController
 35 //设置句柄, 通过句柄对数据库进行操作
 36 static sqlite3 *ppDb = nil;
 37 
 38 - (void)viewDidLoad {
 39     [super viewDidLoad];
 40   
 41     NSLog(@"%@", FileName);
 42     
 43     [self open];
 44 }
 45 
 46 /** 创建一个独立的执行sql语句的方法，传入sql语句，就执行sql语句 */
 47 -(void)execSql:(NSString *)sql {
 48     
 49     char *errmsg; //错误信息
 50     
 51     if (sqlite3_exec(ppDb, [sql UTF8String], NULL, NULL, &errmsg) != SQLITE_OK) {
 52         sqlite3_close(ppDb);
 53         NSLog(@"数据库操作数据失败!");
 54     }
 55 
 56 }
 57 
 58 /** 打开数据库（如果没有就会新建一个） */
 59 - (void)open {
 60     
 61     //操作代码(sql)用来创建表格，注意要转换为c的字符串，结束处有 ; 符号
 62     NSString *sql = @"create table if not exists personinfo (id integer primary key autoincrement,name text, age integer, address text);";
 63     
 64     if (sqlite3_open([FileName UTF8String], &ppDb) == SQLITE_OK) {
 65         
 66         char *errmsg; //错误信息
 67         
 68         //建表
 69         sqlite3_exec(ppDb, [sql UTF8String], NULL, NULL, &errmsg);
 70         if (errmsg) {
 71             NSLog(@"建表失败 -- %s",errmsg);
 72         }
 73         
 74     }else {
 75         NSLog(@"打开数据库失败！");
 76     }
 77     
 78 }
 79 
 80 /** 增 */
 81 - (IBAction)insert {
 82     
 83     NSString *sql1 = [NSString stringWithFormat:@"insert into personinfo (name, age, address) values(‘%@‘, ‘%@‘, ‘%@‘);", @"赵一",  @"20",  @"北京"];
 84     NSString *sql2 = [NSString stringWithFormat:@"insert into personinfo (name, age, address) values(‘%@‘, ‘%@‘, ‘%@‘);", @"钱二",  @"22",  @"上海"];
 85     NSString *sql3 = [NSString stringWithFormat:@"insert into personinfo (name, age, address) values(‘%@‘, ‘%@‘, ‘%@‘);", @"张三",  @"24",  @"广州"];
 86     NSString *sql4 = [NSString stringWithFormat:@"insert into personinfo (name, age, address) values(‘%@‘, ‘%@‘, ‘%@‘);", @"李四",  @"23",  @"深圳"];
 87     NSString *sql5 = [NSString stringWithFormat:@"insert into personinfo (name, age, address) values(‘%@‘, ‘%@‘, ‘%@‘);", @"刘五",  @"26",  @"北京"];
 88 
 89     [self execSql:sql1];
 90     [self execSql:sql2];
 91     [self execSql:sql3];
 92     [self execSql:sql4];
 93     [self execSql:sql5];
 94     
 95 }
 96 
 97 /** 删 */
 98 - (IBAction)delete {
 99     
100     //删除id 大于1 且 小于4 的数据
101     NSString *sql = @"delete from personinfo where id > 1 and id < 4;";
102     [self execSql:sql];
103     
104 }
105 
106 /** 改 */
107 - (IBAction)update {
108     
109     //这里把id为“1”的”name”更改为 “Hello World”
110     NSString *sql = @"update personinfo set name = ‘Hello World‘ where id = 1;";
111     [self execSql:sql];
112     
113 }
114 
115 /** 查 */
116 - (IBAction)select {
117     
118     //打开数据库
119     [self open];
120     
121     //查询所有信息
122 //    NSString *sql = @"select * from personinfo;";
123     //按条件查询
124 //    NSString *sql = @"select * from personinfo where age > 21 and age < 23;";
125 //    NSString *sql = @"select * from personinfo where age between 20 and 22;";
126 //    NSString *sql = @"select * from personinfo where address in (‘北京‘, ‘深圳‘);";
127     NSString *sql = @"select * from personinfo where address in (‘北京‘, ‘深圳‘) and age between 23 and 26;";
128     
129     //查询的句柄,游标
130     sqlite3_stmt *stmt;
131     
132     if (sqlite3_prepare(ppDb, [sql UTF8String], -1, &stmt, NULL) == SQLITE_OK) {
133         
134         //查询数据
135         while (sqlite3_step(stmt) == SQLITE_ROW) {
136             
137             /** 
138              * 获取表数据的内容
139              * sqlite3_column_text(‘句柄‘，字段索引值。为char类型)
140              * sqlite3_column_int(int类型)
141              */
142             
143             NSString *name    = [NSString stringWithCString:(const char *)sqlite3_column_text(stmt, 1) encoding:NSUTF8StringEncoding];
144             int age           = sqlite3_column_int(stmt, 2);
145             NSString *address = [NSString stringWithCString:(const char *)sqlite3_column_text(stmt, 3) encoding:NSUTF8StringEncoding];
146             
147             NSLog(@"name:%@, age:%d, address:%@", name, age, address);
148             
149         }
150         
151     }
152     
153 }
154 
155 @end