iOS 使用FMDB進行數據庫操作
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。
+(NSString *)databaseFilePath
{
NSArray *filePath = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentPath = [filePath objectAtIndex:0];
NSLog(@"%@",filePath);
NSString *dbFilePath = [documentPath stringByAppendingPathComponent:@"db.sqlite"];
return dbFilePath;
}
3、創建數據庫的操作
+(void)creatDatabase
{
db = [[FMDatabasedatabaseWithPath:[selfdatabaseFilePath]] retain];
}
4、創建表
+(void)creatTable
{
//先判斷數據庫是否存在，如果不存在，創建數據庫
if (!db) {
[selfcreatDatabase];
}
//判斷數據庫是否已經打開，如果沒有打開，提示失敗
if (![db open]) {
NSLog(@"數據庫打開失敗");
return;
}
//爲數據庫設置緩存，提高查詢效率
[dbsetShouldCacheStatements:YES];
//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
if(![dbtableExists:@"people"])
{
[db executeUpdate:@"CREATE TABLES people(people_id INTEGER PRIMARY KEY AUTOINCREAMENT, name TEXT, age INTEGER) "];
NSLog(@"創建完成");
}
}
5、增加表數據
+(void)insertPeople:(People *)aPeople
{
if (!db) {
[selfcreatDatabase];
}
if (![db open]) {
NSLog(@"數據庫打開失敗");
return;
}
[dbsetShouldCacheStatements:YES];
if(![dbtableExists:@"people"])
{
[selfcreatTable];
}
//以上操作與創建表是做的判斷邏輯相同
//現在表中查詢有沒有相同的元素，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]];
}
//向數據庫中插入一條數據
else{
[dbexecuteUpdate:@"INSERT INTO people (name, age) VALUES (?,?)",aPeople.name,[NSStringstringWithFormat:@"%d",aPeople.age]];
}
}
6、刪除數據
+(void)deletePeopleByID:(int)ID
{
if (!db) {
[selfcreatDatabase];
}
if (![db open]) {
NSLog(@"數據庫打開失敗");
return;
}
[dbsetShouldCacheStatements:YES];
//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
if(![dbtableExists:@"people"])
{
return;
}
//刪除操作
[db executeUpdate:@"delete from people where people_id = ?", [NSStringstringWithFormat:@"%d",ID]];
[db close];
}
7、修改操作與增加操作的步驟一致
8、查詢
+(NSArray *)getAllPeople
{
if (!db) {
[selfcreatDatabase];
}
if (![db open]) {
NSLog(@"數據庫打開失敗");
return nil;
}
[dbsetShouldCacheStatements:YES];
if(![dbtableExists:@"people"])
{
return nil;
}
//定義一個可變數組，用來存放查詢的結果，返回給調用者
NSMutableArray *peopleArray = [[NSMutableArrayalloc] initWithArray:0];
//定義一個結果集，存放查詢的數據
FMResultSet *rs = [dbexecuteQuery:@"select * from people"];
//判斷結果集中是否有數據，如果有則取出數據
while ([rs next]) {
People *aPeople = [[People alloc] init];
aPeople.peopleID = [rs intForColumn:@"people_id"];
aPeople.name = [rs stringForColumn:@"name"];
aPeople.age = [rs intForColumn:@"age"];
//將查詢到的數據放入數組中。
[peopleArray addObject:aPeople];
}
return [peopleArray autorelease];
}