[摘要]本文介绍iOS 使用FMDB进行数据库操作,并提供详细的示例代码供参考。
1、首先要先导入第三方类库FMdatabase。
2、获得存放数据库文件的沙盒地址。
1 | +(NSString *)databaseFilePath |
2 | { |
3 | |
4 | NSArray *filePath = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); |
5 | NSString *documentPath = [filePath objectAtIndex:0]; |
6 | NSLog(@"%@",filePath); |
7 | NSString *dbFilePath = [documentPath stringByAppendingPathComponent:@"db.sqlite"]; |
8 | return dbFilePath; |
9 | |
10 | } |
3、创建数据库的操作
1 | +(void)creatDatabase |
2 | { |
3 | db = [[FMDatabasedatabaseWithPath:[selfdatabaseFilePath]] retain]; |
4 | } |
4、创建表
1 | +(void)creatTable |
2 | { |
3 | //先判断数据库是否存在,如果不存在,创建数据库 |
4 | if (!db) { |
5 | [selfcreatDatabase]; |
6 | } |
7 | //判断数据库是否已经打开,如果没有打开,提示失败 |
8 | if (![db open]) { |
9 | NSLog(@"数据库打开失败"); |
10 | return; |
11 | } |
12 | |
13 | //为数据库设置缓存,提高查询效率 |
14 | [dbsetShouldCacheStatements:YES]; |
15 | |
16 | //判断数据库中是否已经存在这个表,如果不存在则创建该表 |
17 | if(![dbtableExists:@"people"]) |
18 | { |
19 | [db executeUpdate:@"CREATE TABLES people(people_id INTEGER PRIMARY KEY AUTOINCREAMENT, name TEXT, age INTEGER) "]; |
20 | |
21 | |
22 | NSLog(@"创建完成"); |
23 | } |
24 | |
25 | } |
5、增加表数据
1 | +(void)insertPeople:(People *)aPeople |
2 | { |
3 | if (!db) { |
4 | [selfcreatDatabase]; |
5 | } |
6 | |
7 | if (![db open]) { |
8 | NSLog(@"数据库打开失败"); |
9 | return; |
10 | } |
11 | |
12 | [dbsetShouldCacheStatements:YES]; |
13 | |
14 | if(![dbtableExists:@"people"]) |
15 | { |
16 | [selfcreatTable]; |
17 | } |
18 | //以上操作与创建表是做的判断逻辑相同 |
19 | //现在表中查询有没有相同的元素,如果有,做修改操作 |
20 | FMResultSet *rs = [dbexecuteQuery:@"select * from people where people_id = ?",[NSStringstringWithFormat:@"%d",aPeople.peopleID]]; |
21 | if([rs next]) |
22 | { |
23 | NSLog(@"dddddslsdkien"); |
24 | [dbexecuteUpdate:@"update people set name = ?, age = ? where people_id = 1",aPeople.name,[NSStringstringWithFormat:@"%d",aPeople.age]]; |
25 | } |
26 | //向数据库中插入一条数据 |
27 | else{ |
28 | [dbexecuteUpdate:@"INSERT INTO people (name, age) VALUES (?,?)",aPeople.name,[NSStringstringWithFormat:@"%d",aPeople.age]]; |
29 | } |
30 | |
31 | } |
6、删除数据
1 | +(void)deletePeopleByID:(int)ID |
2 | { |
3 | if (!db) { |
4 | [selfcreatDatabase]; |
5 | } |
6 | |
7 | if (![db open]) { |
8 | NSLog(@"数据库打开失败"); |
9 | return; |
10 | } |
11 | |
12 | [dbsetShouldCacheStatements:YES]; |
13 | |
14 | //判断表中是否有指定的数据, 如果没有则无删除的必要,直接return |
15 | if(![dbtableExists:@"people"]) |
16 | { |
17 | return; |
18 | } |
19 | //删除操作 |
20 | [db executeUpdate:@"delete from people where people_id = ?", [NSStringstringWithFormat:@"%d",ID]]; |
21 | |
22 | [db close]; |
23 | } |
7、修改操作与增加操作的步骤一致
8、查询
1 | +(NSArray *)getAllPeople |
2 | { |
3 | |
4 | if (!db) { |
5 | [selfcreatDatabase]; |
6 | } |
7 | |
8 | if (![db open]) { |
9 | NSLog(@"数据库打开失败"); |
10 | return nil; |
11 | } |
12 | |
13 | [dbsetShouldCacheStatements:YES]; |
14 | |
15 | if(![dbtableExists:@"people"]) |
16 | { |
17 | return nil; |
18 | } |
19 | |
20 | //定义一个可变数组,用来存放查询的结果,返回给调用者 |
21 | NSMutableArray *peopleArray = [[NSMutableArrayalloc] initWithArray:0]; |
22 | //定义一个结果集,存放查询的数据 |
23 | FMResultSet *rs = [dbexecuteQuery:@"select * from people"]; |
24 | //判断结果集中是否有数据,如果有则取出数据 |
25 | while ([rs next]) { |
26 | People *aPeople = [[People alloc] init]; |
27 | |
28 | aPeople.peopleID = [rs intForColumn:@"people_id"]; |
29 | aPeople.name = [rs stringForColumn:@"name"]; |
30 | aPeople.age = [rs intForColumn:@"age"]; |
31 | //将查询到的数据放入数组中。 |
32 | [peopleArray addObject:aPeople]; |
33 | } |
34 | return [peopleArray autorelease]; |
35 | } |
时间: 2024-10-03 21:54:14