sqlite3基本操作

　　在移动设备上进行高性能高效率的大量数据存储，我们一般用得时sqlite这款轻巧型的数据库，这里介绍其增删改查基本功能

　　在ios开发中我们需要先导入"libsqlite3.dylib"这个动态库，然后在控制器中#import "sqlite3.h"

　　在类扩展中定义成员变量：sqlite3 *_db

　　然后定义数据库文件在手机沙盒中的存储位置以及数据库名称：

NSString *path = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)[0];

NSString *fileName = [path stringByAppendingPathComponent:@"myData.sqlite"];

　　执行打开数据库操作：sqlite3_open([fileName UTF8String], &_db)

　　如果数据库是正常打开，我们可以根据需要来创建数据表：

CREATE TABLE IF NOT EXISTS cPerson(id INTEGER PRIMARY KEY AUTOINCREMENT,name TEXT,age INTEGER)

　　然后可以对数据表的数据进行增删改查等操作：

　　增：INSERT INTO cPerson (id, name, age) VALUES ('2','hehe','20')"

　　删：DELETE FROM cPerson WHERE id = 2

　　改：UPDATE cPerson set name = 'ashui' where id = 2

　　查：SELECT * FROM cPerson

　　最后执行关闭数据库操作：sqlite3_close(_db)

　　绑定VALUES(?,?)中?的值：sqlite3_bind_text(sqlite3_stmt *, int, const char *,int n, void (*)(void *))

　　具体代码实现：

 #import "WYSViewController.h"
 #import "sqlite3.h"

 @interface WYSViewController (){

     // 数据库
     sqlite3 *_db;
 }

 @end

 @implementation WYSViewController

 - (void)viewDidLoad
 {
     [super viewDidLoad];

     NSString *path = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)[];
     NSString *fileName = [path stringByAppendingPathComponent:@"myData.sqlite"];

     // 打开数据库
     if (sqlite3_open([fileName UTF8String], &_db) == SQLITE_OK){

         NSLog(@"数据库打开成功");

         // 如果不存在，则创建表
         NSString *cPerson = [NSString stringWithFormat:@"CREATE TABLE IF NOT EXISTS cPerson(id integer primary key autoincrement,name text,age integer)"];
         [self executeWithString:cPerson];

     }
 }

 // 执行操作
 - (void)executeWithString:(NSString *)string
 {
     char *error = nil;

     if (sqlite3_exec(_db, [string UTF8String], NULL, NULL, &error) == SQLITE_OK){

         NSLog(@"操作成功");
     }

 }

 - (IBAction)insertData:(id)sender{

     NSString *iP1 = [NSString stringWithFormat:@"INSERT INTO cPerson (id, name, age) VALUES ('%d','%@','%d')",,@"hehe",];
     [self executeWithString:iP1];

     NSString *iP2 = [NSString stringWithFormat:@"INSERT INTO cPerson (id, name, age) VALUES ('%d','%@','%d')",,@"haha",];
     [self executeWithString:iP2];
 }

 // 删除数据
 - (IBAction)deleteData:(id)sender {

     NSString *dPerson = [NSString stringWithFormat:@"DELETE FROM cPerson WHERE id = 2"];

     [self executeWithString:dPerson];

     // 这种删除方式也行
     //    sqlite3_stmt *statement; // 用于保存编译好的SQL语句
     //
     //    if (sqlite3_prepare_v2(_db, [dPerson UTF8String], -1, &statement, nil) == SQLITE_OK){
     //
     //        while (sqlite3_step(statement) == SQLITE_ROW) {
     //
     ////            if (sqlite3_step(statement) == SQLITE_DONE){
     //
     ////            }
     //        }
     //
     //        NSLog(@"删除成功");
     //
     //        sqlite3_finalize(statement);
     //    }

     //    sqlite3_close(_db);
 }

 // 更新数据
 - (IBAction)updataData:(id)sender {

     NSString *uPerson = [NSString stringWithFormat:@"UPDATE cPerson set name = 'shuige' where id = 3"];

     [self executeWithString:uPerson];

 }

 // 查询数据
 - (IBAction)selectData:(id)sender {

     NSString *sPerson = @"SELECT * FROM cPerson";
     sqlite3_stmt *statement;

     if (sqlite3_prepare_v2(_db, [sPerson UTF8String], -, &statement, nil) == SQLITE_OK){

         while(sqlite3_step(statement) == SQLITE_ROW){

             int id = sqlite3_column_int(statement, );

             char *name = (char *)sqlite3_column_text(statement, );

             NSString *nameStr = [[NSString alloc] initWithUTF8String:name];

             int age = sqlite3_column_int(statement, );

             NSLog(@"id:%d  name:%@   age:%d",id,nameStr,age);
         }

         sqlite3_finalize(statement);
     }

 }
 @end