iOS 使用FMDB进行数据库操作

[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。

View Row Code

1	+(NSString*)databaseFilePath
2	{
3
4	NSArray*filePath=NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES);
5	NSString*documentPath=[filePathobjectAtIndex:0];
6	NSLog(@"%@",filePath);
7	NSString*dbFilePath=[documentPathstringByAppendingPathComponent:@"db.sqlite"];
8	return dbFilePath;
9
10	}

3、创建数据库的操作

View Row Code

1	+(void)creatDatabase
2	{
3	db = [[FMDatabasedatabaseWithPath:[selfdatabaseFilePath]]retain];
4	}

4、创建表

View Row Code

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 (![dbopen]) {
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	[dbexecuteUpdate:@"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

View Row Code

1	+(void)insertPeople:(People*)aPeople
2	{
3	if (!db) {
4	[selfcreatDatabase];
5	}
6
7	if (![dbopen]) {
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([rsnext])
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

View Row Code

1	+(void)deletePeopleByID:(int)ID
2	{
3	if (!db) {
4	[selfcreatDatabase];
5	}
6
7	if (![dbopen]) {
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	[dbexecuteUpdate:@"delete from people where people_id = ?",[NSStringstringWithFormat:@"%d",ID]];
21
22	[dbclose];
23	}

7、修改操作与增加操作的步骤一致

8、查询

View Row Code

1	+(NSArray*)getAllPeople
2	{
3
4	if (!db) {
5	[selfcreatDatabase];
6	}
7
8	if (![dbopen]) {
9	NSLog(@"数据库打开失败");
10	returnnil;
11	}
12
13	[dbsetShouldCacheStatements:YES];
14
15	if(![dbtableExists:@"people"])
16	{
17	returnnil;
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 ([rsnext]) {
26	People*aPeople=[[Peoplealloc]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	[peopleArrayaddObject:aPeople];
33	}
34	return[peopleArrayautorelease];
35	}