IOS-SQLite3的封装

IWStudent.h

 //
 //  IWStudent.h
 //  02-SQLite的封装
 //
 //  Created by apple on 14-5-22.
 //  Copyright (c) 2014年 itcast. All rights reserved.
 //

 #import <Foundation/Foundation.h>

 @interface IWStudent : NSObject
 @property (nonatomic, assign) int ID;
 @property (nonatomic, copy) NSString *name;
 @property (nonatomic, assign) int age;
 @end

 //
 //  IWStudent.m
 //  02-SQLite的封装
 //
 //  Created by apple on 14-5-22.
 //  Copyright (c) 2014年 itcast. All rights reserved.
 //

 #import "IWStudent.h"

 @implementation IWStudent

 @end

IWStudentTool.h

 //
 //  IWStudentTool.h
 //  02-SQLite的封装
 //
 //  Created by apple on 14-5-22.
 //  Copyright (c) 2014年 itcast. All rights reserved.
 //  学生数据的CRUD（增删改查）

 #import <Foundation/Foundation.h>
 @class IWStudent;

 @interface IWStudentTool : NSObject

 /**
  *  添加学生
  *
  *  @param student 需要添加的学生
  */
 + (BOOL)addStudent:(IWStudent *)student;

 /**
  *  获得所有的学生
  *
  *  @return 数组中装着都是IWStudent模型
  */
 + (NSArray *)students;

 /**
  *  根据搜索条件获得对应的学生
  *
  *  @param condition 搜索条件
  */
 + (NSArray *)studentsWithCondition:(NSString *)condition;

 @end

 //
 //  IWStudentTool.m
 //  02-SQLite的封装
 //
 //  Created by apple on 14-5-22.
 //  Copyright (c) 2014年 itcast. All rights reserved.
 //

 #import "IWStudentTool.h"
 #import "IWStudent.h"
 #import <sqlite3.h>

 @implementation IWStudentTool

 // static的作用：能保证_db这个变量只被IWStudentTool.m直接访问
 static sqlite3 *_db;

 + (void)initialize
 {
     // 0.获得沙盒中的数据库文件名
     NSString *filename = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:@"student.sqlite"];

     // 1.创建(打开)数据库（如果数据库文件不存在，会自动创建）
     int result = sqlite3_open(filename.UTF8String, &_db);
     if (result == SQLITE_OK) {
         NSLog(@"成功打开数据库");

         // 2.创表
         const char *sql = "create table if not exists t_student (id integer primary key autoincrement, name text, age integer);";
         char *errorMesg = NULL;
         int result = sqlite3_exec(_db, sql, NULL, NULL, &errorMesg);
         if (result == SQLITE_OK) {
             NSLog(@"成功创建t_student表");
         } else {
             NSLog(@"创建t_student表失败:%s", errorMesg);
         }
     } else {
         NSLog(@"打开数据库失败");
     }
 }

 + (BOOL)addStudent:(IWStudent *)student
 {
     NSString *sql = [NSString stringWithFormat:@"insert into t_student (name, age) values('%@', %d);", student.name, student.age];

     char *errorMesg = NULL;
     int result = sqlite3_exec(_db, sql.UTF8String, NULL, NULL, &errorMesg);

     return result == SQLITE_OK;
 }

 + (NSArray *)students
 {
     // 0.定义数组
     NSMutableArray *students = nil;

     // 1.定义sql语句
     const char *sql = "select id, name, age from t_student;";

     // 2.定义一个stmt存放结果集
     sqlite3_stmt *stmt = NULL;

     // 3.检测SQL语句的合法性
     int result = sqlite3_prepare_v2(_db, sql, -, &stmt, NULL);
     if (result == SQLITE_OK) {
         NSLog(@"查询语句是合法的");
         students = [NSMutableArray array];

         // 4.执行SQL语句，从结果集中取出数据
         while (sqlite3_step(stmt) == SQLITE_ROW) { // 真的查询到一行数据
             // 获得这行对应的数据

             IWStudent *student = [[IWStudent alloc] init];

             // 获得第0列的id
             student.ID = sqlite3_column_int(stmt, );

             // 获得第1列的name
             const unsigned char *sname = sqlite3_column_text(stmt, );
             student.name = [NSString stringWithUTF8String:(const char *)sname];

             // 获得第2列的age
             student.age = sqlite3_column_int(stmt, );

             // 添加到数组
             [students addObject:student];
         }
     } else {
         NSLog(@"查询语句非合法");
     }

     return students;
 }

 + (NSArray *)studentsWithCondition:(NSString *)condition
 {
     // 0.定义数组
     NSMutableArray *students = nil;

     // 1.定义sql语句
     const char *sql = "select id, name, age from t_student where name like ?;";

     // 2.定义一个stmt存放结果集
     sqlite3_stmt *stmt = NULL;

     // 3.检测SQL语句的合法性
     int result = sqlite3_prepare_v2(_db, sql, -, &stmt, NULL);
     if (result == SQLITE_OK) {
         NSLog(@"查询语句是合法的");
         students = [NSMutableArray array];

         // 填补占位符的内容
         NSString *newCondition = [NSString stringWithFormat:@"%%%@%%", condition];
 //        NSLog(@"%@", newCondition);
         sqlite3_bind_text(stmt, , newCondition.UTF8String, -, NULL);

         // 4.执行SQL语句，从结果集中取出数据
         while (sqlite3_step(stmt) == SQLITE_ROW) { // 真的查询到一行数据
             // 获得这行对应的数据

             IWStudent *student = [[IWStudent alloc] init];

             // 获得第0列的id
             student.ID = sqlite3_column_int(stmt, );

             // 获得第1列的name
             const unsigned char *sname = sqlite3_column_text(stmt, );
             student.name = [NSString stringWithUTF8String:(const char *)sname];

             // 获得第2列的age
             student.age = sqlite3_column_int(stmt, );

             // 添加到数组
             [students addObject:student];
         }
     } else {
         NSLog(@"查询语句非合法");
     }

     return students;
 }
 @end

IWViewController.m

 //
 //  IWViewController.m
 //  01-SQLite的基本使用
 //
 //  Created by apple on 14-5-22.
 //  Copyright (c) 2014年 itcast. All rights reserved.
 //

 #import "IWViewController.h"
 #import "IWStudent.h"
 #import "IWStudentTool.h"

 //Core Data : 苹果官方自带，可以让程序员不用写任何一句SQL
 //FMDB

 @interface IWViewController () <UISearchBarDelegate>

 /*
 - (IBAction)insert;
 - (IBAction)update;
 - (IBAction)delete;
 - (IBAction)query;
 */

 @property (nonatomic, strong) NSArray *students;
 @end

 @implementation IWViewController

 - (NSArray *)students
 {
     if (_students == nil) {
         _students = [IWStudentTool students];
     }
     return _students;
 }

 - (void)viewDidLoad
 {
     [super viewDidLoad];

     UISearchBar *searchBar = [[UISearchBar alloc] initWithFrame:CGRectMake(, , , )];
     searchBar.delegate = self;
     self.tableView.tableHeaderView = searchBar;
 }

 #pragma mark - 搜索框代理
 - (void)searchBar:(UISearchBar *)searchBar textDidChange:(NSString *)searchText
 {
     self.students = [IWStudentTool studentsWithCondition:searchText];
     [self.tableView reloadData];
 }

 #pragma mark - tableView代理方法
 - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
 {
     return self.students.count;
 }

 - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
 {
     // 1.创建cell
     static NSString *ID = @"student";
     UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:ID];
     if (cell == nil) {
         cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:ID];
     }

     // 2.设置cell的数据
     IWStudent *stu = self.students[indexPath.row];
     cell.textLabel.text = stu.name;
     cell.detailTextLabel.text = [NSString stringWithFormat:@"%d", stu.age];

     return cell;
 }

 /*
 - (IBAction)insert
 {
     for (int i = 0; i<30; i++) {
         // 创建学生
         IWStudent *student = [[IWStudent alloc] init];
         student.name = [NSString stringWithFormat:@"Jack-%d", arc4random()%100];
         student.age = arc4random()%100;

         // 添加学生
         BOOL result = [IWStudentTool addStudent:student];

         if (result) {
             NSLog(@"添加成功");
         }
     }
 }

 - (IBAction)update
 {

 }

 - (IBAction)delete
 {

 }

 - (IBAction)query
 {
     NSArray *students = [IWStudentTool students];

     for (IWStudent *stu in students) {
         NSLog(@"%d %@ %d", stu.ID, stu.name, stu.age);
     }
 }
  */
 @end