iOS 使用FMDB進行數據庫操作

iOS 使用FMDB進行數據庫操作

2012-11-06 19:48 來源：博客園 作者：lzz900201 字號：T|T

[摘要]本文介紹iOS 使用FMDB進行數據庫操作，並提供詳細的示例代碼供參考。

1、首先要先導入第三方類庫FMdatabase。

2、獲得存放數據庫文件的沙盒地址。

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、創建數據庫的操作

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

4、創建表

1	+(void)creatTable
2	{
3	//先判斷數據庫是否存在，如果不存在，創建數據庫
4	if (!db) {
5	[selfcreatDatabase];
6	}
7	//判斷數據庫是否已經打開，如果沒有打開，提示失敗
8	if (![db open]) {
9	NSLog(@"數據庫打開失敗");
10	return;
11	}
12
13	//爲數據庫設置緩存，提高查詢效率
14	[dbsetShouldCacheStatements:YES];
15
16	//判斷數據庫中是否已經存在這個表，如果不存在則創建該表
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(@"創建完成");
23	}
24
25	}

5、增加表數據

View Row Code

1	+(void)insertPeople:(People *)aPeople
2	{
3	if (!db) {
4	[selfcreatDatabase];
5	}
6
7	if (![db open]) {
8	NSLog(@"數據庫打開失敗");
9	return;
10	}
11
12	[dbsetShouldCacheStatements:YES];
13
14	if(![dbtableExists:@"people"])
15	{
16	[selfcreatTable];
17	}
18	//以上操作與創建表是做的判斷邏輯相同
19	//現在表中查詢有沒有相同的元素，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	//向數據庫中插入一條數據
27	else{
28	[dbexecuteUpdate:@"INSERT INTO people (name, age) VALUES (?,?)",aPeople.name,[NSStringstringWithFormat:@"%d",aPeople.age]];
29	}
30
31	}

6、刪除數據

1	+(void)deletePeopleByID:(int)ID
2	{
3	if (!db) {
4	[selfcreatDatabase];
5	}
6
7	if (![db open]) {
8	NSLog(@"數據庫打開失敗");
9	return;
10	}
11
12	[dbsetShouldCacheStatements:YES];
13
14	//判斷表中是否有指定的數據， 如果沒有則無刪除的必要，直接return
15	if(![dbtableExists:@"people"])
16	{
17	return;
18	}
19	//刪除操作
20	[db executeUpdate:@"delete from people where people_id = ?", [NSStringstringWithFormat:@"%d",ID]];
21
22	[db close];
23	}

7、修改操作與增加操作的步驟一致

8、查詢

1	+(NSArray *)getAllPeople
2	{
3
4	if (!db) {
5	[selfcreatDatabase];
6	}
7
8	if (![db open]) {
9	NSLog(@"數據庫打開失敗");
10	return nil;
11	}
12
13	[dbsetShouldCacheStatements:YES];
14
15	if(![dbtableExists:@"people"])
16	{
17	return nil;
18	}
19
20	//定義一個可變數組，用來存放查詢的結果，返回給調用者
21	NSMutableArray *peopleArray = [[NSMutableArrayalloc] initWithArray:0];
22	//定義一個結果集，存放查詢的數據
23	FMResultSet *rs = [dbexecuteQuery:@"select * from people"];
24	//判斷結果集中是否有數據，如果有則取出數據
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	//將查詢到的數據放入數組中。
32	[peopleArray addObject:aPeople];
33	}
34	return [peopleArray autorelease];
35	}