0427 数据库 是否存在文件名

//Documents:

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);

    //username md5

    const char *cStr = [userName UTF8String];

    unsigned char result[16];

    CC_MD5(cStr, (CC_LONG)strlen(cStr), result);

    NSString* MD5 =  [NSString stringWithFormat:@"%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x",result[0], result[1], result[2], result[3], result[4], result[5], result[6], result[7],result[8], result[9], result[10], result[11],result[12], result[13], result[14], result[15]];

    //数据库文件夹

    NSString * documentsDirectory = [[paths objectAtIndex:0] stringByAppendingPathComponent:MD5];

    NSFileManager *fileManager = [NSFileManager defaultManager];

    BOOL isDir = FALSE;

    BOOL isDirExist = [fileManager fileExistsAtPath:documentsDirectory isDirectory:&isDir];

    if(!(isDirExist && isDir)) {

        BOOL bCreateDir = [fileManager createDirectoryAtPath:documentsDirectory withIntermediateDirectories:YES attributes:nil error:nil];

        if(!bCreateDir) {

            MCLog(@"Create Database Directory Failed.");

        }

        MCLog(@"%@", documentsDirectory);

    }

    NSString *dbPath = [documentsDirectory stringByAppendingPathComponent:@"im_demo.db"];

    MCLog(@"im_demo.db 数据库地址 ===%@",dbPath);

    if (self.dataBase) {

        [self.dataBase close];

        self.dataBase = nil;

    }

    self.dataBase = [FMDatabase databaseWithPath:dbPath];

    [self.dataBase open];

    [self memberTableCreate];//成员表 gzz0427

    [self IMGroupIDTableCreate];

    [self IMGroupNoticeTableCreate];

    [self sessionTableCreate];    //会话表   gzz0427

    [self IMTriggerCreate]; //触发器???

0427 数据库 是否存在文件名

原文：http://www.cnblogs.com/gzz2016/p/5439592.html