iOS关于数据库的操作（使用第三方类库FMDB）

首先要先导入第三方类库FMdatabase
获得存放数据库文件的沙盒地址

+(NSString *)databaseFilePath

{

 

NSArray *filePath = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentPath = [filePath objectAtIndex:0];
NSLog(@"%@",filePath);
NSString *dbFilePath = [documentPath stringByAppendingPathComponent:@"db.sqlite"];
return dbFilePath; 

 

}

创建数据库的操作

+(void)creatDatabase

{

db= [[FMDatabasedatabaseWithPath:[selfdatabaseFilePath]] retain];

}

创建表

+(void)creatTable

{

//先判断数据库是否存在，如果不存在，创建数据库if(!db) {
[selfcreatDatabase];
}
//判断数据库是否已经打开，如果没有打开，提示失败 
if(![db open]) {
NSLog(@"数据库打开失败");
return;
}
//为数据库设置缓存，提高查询效率 
[dbsetShouldCacheStatements:YES];
 //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
if(![dbtableExists:@"people"])
{
[db executeUpdate:@"CREATE TABLES people(people_id INTEGER PRIMARY KEY AUTOINCREAMENT, name TEXT, age INTEGER) "];
 
 
NSLog(@"创建完成");
}

 

}

增加表数据

+(void)insertPeople:(People*)aPeople

{

if(!db) {
[selfcreatDatabase];
}
 
if(![db open]) {
NSLog(@"数据库打开失败");
return;
}
 
[dbsetShouldCacheStatements:YES];
 
if(![dbtableExists:@"people"])
{
[selfcreatTable];
}
//以上操作与创建表是做的判断逻辑相同//现在表中查询有没有相同的元素，如果有，做修改操作 
FMResultSet*rs = [dbexecuteQuery:@"select * from people where people_id = ?",[NSStringstringWithFormat:@"%d",aPeople.peopleID]];
if([rs next]) {
NSLog(@"dddddslsdkien");
[dbexecuteUpdate:@"update people set name = ?, age = ? where people_id = 1",aPeople.name,[NSStringstringWithFormat:@"%d",aPeople.age]];
}
//向数据库中插入一条数据 
else{
[dbexecuteUpdate:@"INSERT INTO people (name, age) VALUES (?,?)",aPeople.name,[NSStringstringWithFormat:@"%d",aPeople.age]];
}

 

 

}

删除数据

+(void)deletePeopleByID:(int)ID

{

if(!db) {
[selfcreatDatabase];
}
 
if(![db open]) {
NSLog(@"数据库打开失败");
return;
}
 
[dbsetShouldCacheStatements:YES];
 //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
if(![dbtableExists:@"people"])
{
return;
}
//删除操作 
[db executeUpdate:@"delete from people where people_id = ?", [NSStringstringWithFormat:@"%d",ID]];
[db close];

}

修改操作与增加操作的步骤一致
查询

+(NSArray*)getAllPeople

{

 
if(!db) {
[selfcreatDatabase];
}
 
if(![db open]) {
NSLog(@"数据库打开失败");
return nil;
}
 
[dbsetShouldCacheStatements:YES];
 
if(![dbtableExists:@"people"])
{
return nil;
}
//定义一个可变数组，用来存放查询的结果，返回给调用者 
NSMutableArray*peopleArray = [[NSMutableArrayalloc] initWithArray:0];//定义一个结果集，存放查询的数据
FMResultSet*rs = [dbexecuteQuery:@"select * from people"];//判断结果集中是否有数据，如果有则取出数据
while([rs next]) {
People*aPeople = [[People alloc] init];
 
aPeople.peopleID= [rs intForColumn:@"people_id"];
aPeople.name= [rs stringForColumn:@"name"];
aPeople.age= [rs intForColumn:@"age"];
//将查询到的数据放入数组中。 
[peopleArray addObject:aPeople];}
return[peopleArray autorelease];

}

原文地址：http://www.cnblogs.com/lzz900201/archive/2012/11/06/2756284.html