Question

我正在Xcode中开发一个iPhone应用程序，我无法访问我创建的数据库。以下是我创建数据库的代码

//create local database
NSString *docsDir;
NSArray *dirPaths;
sqlite3 *localDB;

// Get the documents directory
dirPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
docsDir = [dirPaths objectAtIndex:0];

// Build the path to the database file
databasePath = [[NSString alloc] initWithString: [docsDir stringByAppendingPathComponent: @"local.db"]];

NSFileManager *filemgr = [NSFileManager defaultManager];

if ([filemgr fileExistsAtPath: databasePath ] == NO) {
    const char *dbpath = [databasePath UTF8String];

    if (sqlite3_open(dbpath, &localDB) == SQLITE_OK) {
        char *errMsg;
        const char *sql_stmt1 = "CREATE TABLE IF NOT EXISTS My_choices (perfume_id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT, na TEXT, got_it TEXT)";

        const char *sql_stmt2 = "CREATE TABLE IF NOT EXISTS Ratings (perfume_id INTEGER PRIMARY KEY AUTOINCREMENT, rating NUMERIC)";

        const char *sql_stmt3 = "CREATE TABLE IF NOT EXISTS Consultant_Details (_id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT,website TEXT,domain TEXT,domain_no NUMERIC,phone TEXT,facebook TEXT)";

        if (sqlite3_exec(localDB, sql_stmt1, NULL, NULL, &errMsg) != SQLITE_OK) {
            NSLog(@"%@",@"Failed to create table My_choices");

        }
        if (sqlite3_exec(localDB, sql_stmt2, NULL, NULL, &errMsg) != SQLITE_OK) {
            NSLog(@"%@",@"Failed to create table ratings");

        }
        if (sqlite3_exec(localDB, sql_stmt3, NULL, NULL, &errMsg) != SQLITE_OK) {
            NSLog(@"%@",@"Failed to create table Consultant_Details");

        }


        sqlite3_close(localDB);
    }
    else {
        NSLog(@"%@",@"Failed to open/create database");

    }
}

下面添加的是我尝试访问它的代码

NSString *docsDir;
NSArray *dirPaths;
sqlite3 *localDB;

// Get the documents directory
dirPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
docsDir = [dirPaths objectAtIndex:0];

// Build the path to the database file
NSString *dbPath = [[NSString alloc] initWithString: [docsDir stringByAppendingPathComponent: @"local.db"]];


NSString *q = @"select * from Ratings where perfume_id in";

q = [q stringByAppendingString:idList];

NSLog(@"%@",q);
const char *sqlStatement2 = [q UTF8String];
sqlite3_stmt *compiledStatement2;
if(sqlite3_open([dbPath UTF8String], &localDB) == SQLITE_OK) {
    if(sqlite3_prepare_v2(localDB, sqlStatement2, -1, &compiledStatement2, NULL) == SQLITE_OK) {

        NSLog(@"%d",  SQLITE_ROW);
        // Loop through the results and add them to the feeds array
        while(sqlite3_step(compiledStatement2) == SQLITE_ROW) {


            // Read the data from the result row
            int r = sqlite3_column_int(compiledStatement2, 1);
            int id = sqlite3_column_int(compiledStatement2, 0);
            NSLog(@"%d", id);

            for (ListItem *item in self.listItemArray) {

                if(item.perfumeId == id){
                    item.rating = r;

                }
            }

        }
    }
    else{
        NSLog(@"query failed: %s", sqlite3_errmsg(localDB));
    }
}
sqlite3_close(localDB);

我总是得到＆＃34;查询失败没有这样的表存在：评级＆＃34;在我的日志中。任何帮助将不胜感激。

Answer 1

基本上由于数据库中的表不可用或查询错误而发生此错误。根据您的帖子，IT在查询中看起来像是一个错误。

查询应该是这样的：

NSString *q = @"select * from Ratings where perfume_id in ('12','13','14','15')";

打印您的"String q"，并确保按照上述步骤进行操作。

Answer 2

感谢大家的帮助。在该路径上已存在相同的数据库文件。所以我的第一个方法是创建一个数据库 if（[filemgr fileExistsAtPath：databasePath] == NO）check is false且未创建表。

Answer 3

首先从文档目录中删除数据库文件，然后使用以下代码创建一个sqlite表..

 if (![fileManager fileExistsAtPath: _databasePath ])
        {
            const char *dbpath = [_databasePath UTF8String];
            if (sqlite3_open(dbpath, &_myDataBase) == SQLITE_OK)
            {
                char *errMsg;
                const char *sql_stmt =
                "CREATE TABLE IF NOT EXISTS My_choices (perfume_id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT, na TEXT, got_it TEXT);" //TEST
                "CREATE TABLE IF NOT EXISTS Ratings (perfume_id INTEGER PRIMARY KEY AUTOINCREMENT, rating NUMERIC);" //USER
                "CREATE TABLE IF NOT EXISTS Consultant_Details (_id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT,website TEXT,domain TEXT,domain_no NUMERIC,phone TEXT,facebook TEXT)"; //METADATA


                if (sqlite3_exec(_myDataBase, sql_stmt, NULL, NULL, &errMsg) != SQLITE_OK)
                {
                    NSLog(@"Failed to create tables");
                }
                sqlite3_close(_myDataBase);
                NSLog(@"DataBase created at: %@",_databasePath);
            } else {
                NSLog(@"Failed to open/create database");
            }
        }

Sqlite3数据库没有执行查询

3 个答案: