#import <Foundation/Foundation.h>
#import "Student.h"
@interface DataBaseHandle : NSObject
+ (DataBaseHandle *)shareDataBase;
- (void)openDB;
- (void)closeDB;
//添加数据
- (void)insertNewStudent:(Student *)student;
/***  根据学号查询学生*/
- (Student *)selectStudentWithNumber:(NSInteger)number;
/***  查询表中所有数据*/
- (NSMutableArray *)selectAllStudents;
/***  根据学号删除*/
- (void)deleteStudentWithNumber:(NSInteger)number;
- (void)updateStudent:(NSString *)gender WithNumber:(NSInteger)number;
@end

+ (DataBaseHandle *)shareDataBase {@synchronized (self){if (handle == nil) {handle = [[DataBaseHandle alloc] init];//            [handle closeDB];}}return handle;
}
sqlite3 *db = nil;

- (void)openDB {NSString *str = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)firstObject];NSString *path = [str stringByAppendingPathComponent:@"student.sqlite"];NSLog(@"%@",path);//打开数据库//UTF8String 将oc字符串转化为C语言字符串//方法执行完会返回一个数据库对象，这个对象已被初始化int result = sqlite3_open([path UTF8String], &db);//如果等于SQLITE_OK说明sql语句执行成功if (result == SQLITE_OK) {NSLog(@"数据库打开成功");//创建表格NSString *sqlString = @"create table if not exists Student (number integer primary key autoincrement,name text,gender text,age integer)";int result =  sqlite3_exec(db, [sqlString UTF8String], NULL, NULL, NULL);if (result == SQLITE_OK) {NSLog(@"见表成功");}} else {NSLog(@"数据库打开失败");}
}

- (void)closeDB {int result = sqlite3_close(db);if (result == SQLITE_OK) {NSLog(@"关闭成功");}else {NSLog(@"关闭失败");}
}

- (void)insertNewStudent:(Student *)student {[self openDB];//准备sql语句NSString *sqlString = @"insert into Student (name,gender, age) values (?, ?, ?)";/*第一个参数，数据库指针，第二个参数，sql语句第三个参数，sql语句的长度，写成-1，自动计算第四个参数，创建管理sql语句的类，statement第五个参数，预留参数*/sqlite3_stmt *stmt = nil;int result = sqlite3_prepare_v2(db, [sqlString UTF8String], -1, &stmt, NULL);if (result == SQLITE_OK) {NSLog(@"添加语句成功");//绑定参数//绑定的参数：1.管理类指针，2.第几个问号，3.绑定的数据， 4.绑定数据的长度 -1   5.sqlite3_bind_text(stmt, 1, [student.name UTF8String], -1, NULL);sqlite3_bind_text(stmt, 2, [student.gender UTF8String], -1, NULL);sqlite3_bind_int(stmt, 3, (int)student.age);/**/sqlite3_step(stmt);} else {NSLog(@"添加语句失败");}sqlite3_finalize(stmt);[self closeDB];
}

- (NSMutableArray *)selectAllStudents {[self openDB];NSString *sqlString = @"select * from student";sqlite3_stmt *stmt = nil;int result = sqlite3_prepare_v2(db, [sqlString UTF8String], -1, &stmt, nil);if (result == SQLITE_OK) {NSLog(@"查询全部成功");//循环的条件:下一行还有数据，这时就能一直循环下去NSMutableArray *array = [NSMutableArray arrayWithCapacity:0];while (sqlite3_step(stmt) == SQLITE_ROW) {NSString *name = [NSString stringWithUTF8String:(const char *)sqlite3_column_text(stmt, 1)];NSString *gender = [NSString stringWithUTF8String:(const char *)sqlite3_column_text(stmt, 2)];NSInteger age = sqlite3_column_int(stmt, 3);Student *stu = [[Student alloc] init];stu.name = name;stu.age = age;stu.gender = gender;[array addObject:stu];[stu release];}sqlite3_finalize(stmt);[self closeDB];return array;} else {NSLog(@"error");return nil;}
}

- (Student *)selectStudentWithNumber:(NSInteger)number {[self openDB];NSString *sqlString = @"select * from Student where number = ?";sqlite3_stmt *stmt = nil;int result = sqlite3_prepare_v2(db, [sqlString UTF8String], -1, &stmt, NULL);if (result == SQLITE_OK) {NSLog(@"查询成功");//绑定参数sqlite3_bind_int(stmt, 1, (int)number);Student *student = [[[Student alloc] init]autorelease];while (sqlite3_step(stmt) == SQLITE_ROW) {student.name = [NSString stringWithUTF8String:(const char *)sqlite3_column_text(stmt, 1)];student.gender = [NSString stringWithUTF8String:(const char *)sqlite3_column_text(stmt, 2)];student.age = sqlite3_column_int(stmt, 3);}sqlite3_finalize(stmt);[self closeDB];return student;} else {NSLog(@"不OK");return nil;}
}

- (void)deleteStudentWithNumber:(NSInteger)number {[self openDB];NSString *sqlString = @"delete from Student where number = ?";sqlite3_stmt *stmt = nil;int result = sqlite3_prepare_v2(db, [sqlString UTF8String], -1, &stmt, NULL);if (result == SQLITE_OK) {sqlite3_bind_int(stmt, 1, (int)number);//执行sql语句sqlite3_step(stmt);}//释放stmt的内存资源sqlite3_finalize(stmt);[self closeDB];
}

- (void)updateStudent:(NSString *)gender WithNumber:(NSInteger)number {[self openDB];NSString *sqlString = @"update Student set gender = ? where number = ?";sqlite3_stmt *stmt = nil;int result = sqlite3_prepare_v2(db, [sqlString UTF8String], -1, &stmt, NULL);if (result == SQLITE_OK) {sqlite3_bind_int(stmt, 2, (int)number);sqlite3_step(stmt);}sqlite3_finalize(stmt);[self closeDB];
}