iOS 三方库fmdb 的使用

使用fmdb 做本地数据的存储非常方便，

1. github 上搜索fmdb 下载压缩包 导入到工程中 （如果你的mac 有cocoapod 也可以直接通过cocoapod 添加）

2. 以下代码是通过fmdb 多数据库的各种操作，其中有几点需要注意：（1）. 程序中 Ceasar 是表名   （2）. 修改数据库数据  提前准备字符串时 值 要用单引号括起来 否则会出错 ： NSString *temp = [NSString stringWithFormat:@"UPDATE %@ SET %@ = '%@' WHERE %@ = '%@'",@"Ceasar",@"Name",@"hao",@"Age",[NSNumber numberWithInt:100]];

　　  NSString *path = @"/Users/shijieli/Desktop/test.sqlite";

FMDatabase *db = [FMDatabase databaseWithPath:path];

if ([db open]) {//创建表

BOOL res = [db executeUpdate:@"CREATE TABLE IF NOT EXISTS Ceasar (Name text, Age integer, Photo blob)"];

if (!res) {

NSLog(@"error when creating db table");

} else {

NSLog(@"success to creating db table");

}

[db close];

}

if ([db open]) {//添加数据

BOOL res = [db executeUpdate:@"INSERT INTO Ceasar (Name, Age, Photo) VALUES (?, ?, ?)",@"Gaius",[NSNumber numberWithInteger:100],[NSData dataWithContentsOfFile:@"/Users/shijieli/Desktop/testPicture.jpg"]];

if (res) {

NSLog(@"success to insert db table");

} else {

NSLog(@"error when insert db table");

}

[db close];

}

if ([db open]) {//查询

FMResultSet * rs = [db executeQuery:@"SELECT * FROM Ceasar"];

while ([rs next]) {

NSString * name = [rs stringForColumn:@"Name"];

int age = [rs intForColumn:@"Age"];

NSData *photo = [rs dataForColumn:@"Photo"];

NSLog(@" name = %@, age = %d",  name, age);

BOOL isCreate = [[NSFileManager defaultManager] createFileAtPath:@"/Users/shijieli/Desktop/car.jpg" contents:photo attributes:nil];

if (!isCreate) {

NSLog(@" ****** create failure");

}

}

[db close];

}

//        if ([db open]) {//修改数据

//            NSString *temp = [NSString stringWithFormat:@"UPDATE %@ SET %@ = '%@' WHERE %@ = '%@'",@"Ceasar",@"Name",@"hao",@"Age",[NSNumber numberWithInt:100]];

//            BOOL res = [db executeUpdate:temp];

//            if (!res) {

//                NSLog(@"error when update db table");

//            } else {

//                NSLog(@"success to update db table");

//            }

//

//            [db close];

//

//        }

//        if ([db open]) {//清除表

//            BOOL res = [db executeUpdate:@"DELETE FROM Ceasar"];

//            if (!res) {

//                NSLog(@"delete failure");

//            }

//        }

if ([db open]) {//删除数据

NSString *deleteSql = [NSString stringWithFormat:

@"delete from %@ where %@ = '%@'",

@"Ceasar", @"Name", @"hao"];

BOOL res = [db executeUpdate:deleteSql];

if (!res) {

NSLog(@"error when delete db table");

} else {

NSLog(@"success to delete db table");

}

[db close];

}

}