iOS数据库汇总-----更新不间断

手机通用数据库类型：  sqlite3   
 用sql语句操作数据，不区分大小写
Sqlite3:

1.建表：
         create table if not exists student（stu_No varchar(200),  stu_Name  varchar(300),su_Sex varchar(100),stu_Age  integer） 
 如果不存在学生信息表则创建 表student
creat table+表名(字段名称 字段类型，字段名称 字段类型，)
2.添加数据：
           insert into student（stu_No , stu_Name,stu_Sex,stu_age,stu_Chengji）
 values(‘1000001’,’李雷’，‘F’，18，60)
【注】添加的数据类型如果是字符串类型则要加单引号
3.删除：
        delete from student where stu_No = ’1000001’
删除某一条数据时需要添加where 条件判断
如果不加where条件判断 则 删除表中的全部数据，表仍在，可以继续添加数据操作。
delete from student  
4.修改：
        update student set stu_Sex = ‘M’where stu_No = ’1000001’
修改一条数据需要添加where判断，进行定位数据对象

5.查询：
       select * from student 
查询表中的全部数据
select from student where stu_No = ‘1000001’
按条件查询一行数据
select stu_Name from student where stu_No = ‘1000001’
按条件查询某个字段值
代码如下：
导库：
              


1.创建：
-(void)creatDB{
//沙盒路径 app 所在的位置 都是相对路径
//沙盒目录下 3个 文件夹 Documents Library tmp
//Documents 一般存放数据库或者plist文件，一般用来存放用户信息，
//library/caches 存放一些缓存文件，临时性文件
//tmp 存放临时性文件 app、iphone重启 tmp中文件销毁

//1. 确定数据库文件的路径
// 在沙盒目录下 Documents 下 名称为student.db
NSString *dbPath = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)firstObject] stringByAppendingPathComponent:@"student.db"];

// NSString *dbStr = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents/student.db"];
//2.声明数据库对象
sqlite3 *stuSql = nil;
//3.打开数据库
//parameter1:数据库路径
//parameter2:数据库对象
if (sqlite3_open([dbPath UTF8String], &stuSql) == SQLITE_OK) {
//如果打开数据库成功，则继续 数据库操作

NSString *str = @"create table if not exists student (id integer primary key autoincrement,stu_No varchar(200),stu_Name varchar(200),stu_Sex varchar(200),stu_age integer)";
//sqlite3_exec 执行数据库操作

char *errMsg = nil;
int result = sqlite3_exec(stuSql, [str UTF8String], NULL, NULL, &errMsg);
if (result == SQLITE_OK) {
NSLog(@"建表成功");
}
//关闭数据库
sqlite3_close(stuSql);
}else{
NSLog(@"数据库打开失败 %s",sqlite3_errmsg(stuSql));
sqlite3_close(stuSql);
}
}


2.增：
-(void)addNewData:(UIButton*)btn{
NSString *dbPath = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject] stringByAppendingPathComponent:@"student.db"];
sqlite3 *stusql = nil;

//打开数据库成功
if (sqlite3_open([dbPath UTF8String], &stusql) == SQLITE_OK) {
NSString *insertStr = @"insert into student(stu_No,stu_Name,stu_Sex,stu_age) values('151601','小明','女',46)";
if (sqlite3_exec(stusql, [insertStr UTF8String], NULL, NULL, NULL) == SQLITE_OK) {
NSLog(@"插入一条数据成功");
}else{
NSLog(@"%s",sqlite3_errmsg(stusql));
}
}
sqlite3_close(stusql);
}


3.删：
-(void)delData:(UIButton*)btn{
NSString *dbPath = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)firstObject] stringByAppendingPathComponent:@"student.db"];

sqlite3 *stusql = nil;

if (sqlite3_open([dbPath UTF8String], &stusql) == SQLITE_OK) {
NSString *delStr = @"delete from student where stu_No= '100001'";
if (sqlite3_exec(stusql, [delStr UTF8String], NULL, NULL, NULL) == SQLITE_OK) {

}else{
NSLog(@"%s",sqlite3_errmsg(stusql));
}
}
sqlite3_close(stusql);
}


4.改：
-(void)updateData:(UIButton*)btn{
//数据路径
NSString *dbPath = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)firstObject]stringByAppendingPathComponent:@"student.db"];
//声明数据库对象
sqlite3 *stuSql = nil;

//打开数据库
if (sqlite3_open([dbPath UTF8String], &stuSql) == SQLITE_OK) {
NSString *updateStr = @"update student set stu_Sex = 'unkown' where stu_No = '100001'";
if (sqlite3_exec(stuSql, [updateStr UTF8String], NULL, NULL, NULL) == SQLITE_OK) {
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NSLog(@"更新完成");
}else{
NSLog(@"%s",sqlite3_errmsg(stuSql));
}
}else{
NSLog(@"%s",sqlite3_errmsg(stuSql));
}
sqlite3_close(stuSql);
}


5.查：
-(void)queryData:(UIButton*)btn{
NSString *dbPath = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject] stringByAppendingPathComponent:@"student.db"];

sqlite3 *stuSql = nil;

if (sqlite3_open([dbPath UTF8String], &stuSql) == SQLITE_OK) {
NSString *queryStr = @"select stu_Name from student where stu_Sex = 'unkown'";
// NSString *queryStr = @"select * from student";

//先声明查询句柄
sqlite3_stmt *stmt = nil;
//先做查询前的准备
sqlite3_prepare_v2(stuSql, [queryStr UTF8String], -1, &stmt, nil);
//查询数据时，每行查询一次，放在while中
while (sqlite3_step(stmt) == SQLITE_ROW) {
//sqlite3_column_text 查询当前属性值
//parameter1:查询句柄
//parameter2:当前取得字段在结果集中的列是第几列
char *number = (char*)sqlite3_column_text(stmt, 1);
NSString *numberStr = [NSString stringWithUTF8String:number];
NSLog(@" number: %@",numberStr);

char *nameChar = (char*)sqlite3_column_text(stmt,2);
NSString *nameStr = [NSString stringWithUTF8String:nameChar];
NSLog(@"name: %@",nameStr);

char *sexChar = (char*)sqlite3_column_text(stmt, 3);
NSString *sexStr = [NSString stringWithUTF8String:sexChar];
NSLog(@"sex: %@",sexStr);

}

}else{
NSLog(@"%s",sqlite3_errmsg(stuSql));
}

}