Question

这是我的代码：

在我的ViewDidLoad中创建数据库：

 NSString *docsDir;
    NSArray *dirPaths;

    dirPaths=NSSearchPathForDirectoriesInDomains(NSDocumentationDirectory, NSUserDomainMask, YES);
    docsDir = [dirPaths objectAtIndex:0];
    databasePath = [[NSString alloc] initWithString: [docsDir stringByAppendingPathComponent: @"contacts.db"]];

    NSFileManager *filemgr=[NSFileManager defaultManager];

    if ([filemgr fileExistsAtPath:databasePath]==NO)
    {
        NSLog(@"Creating DB");
        const char *dbpath=[databasePath UTF8String];

        if (sqlite3_open(dbpath, &contactDB)==SQLITE_OK)
        {
            char *error_msg;
            const char *sql_stmt = "CREATE TABLE IF NOT EXISTS CONTACTS (ID INTEGER PRIMARY KEY AUTOINCREMENT, URL TEXT, EMAIL TEXT, CODE TEXT, FULL TEXT)";

            if (sqlite3_exec(contactDB, sql_stmt, NULL, NULL, &error_msg) != SQLITE_OK)
            {
               NSLog(@"Failed to create table");
            }

            sqlite3_close(contactDB);

        } else {
            NSLog(@"Failed to open/create database");
        }
    } else {
        NSLog(@"DB exists");
    }

我可以看到输出消息"Creating DB"

然后我必须在那里添加我的数据：

sqlite3_stmt    *statement;

                const char *dbpath = [databasePath UTF8String];

                if (sqlite3_open(dbpath, &contactDB) == SQLITE_OK)
                {
                    NSString *insertSQL = [NSString stringWithFormat: @"INSERT INTO CONTACTS (url, email, code, full) VALUES (\"%@\", \"%@\", \"%@\", \"%@\")", url_2, mail, keycode,full_2 ];

                    const char *insert_stmt = [insertSQL UTF8String];

                    sqlite3_prepare_v2(contactDB, insert_stmt, -1, &statement, NULL);
                    if (sqlite3_step(statement) == SQLITE_DONE)
                    {
                        NSLog(@"Contact added");
                    } else {
                        NSLog(@"Failed to add contact");
                    }
                    sqlite3_finalize(statement);
                    sqlite3_close(contactDB);
                } else {
                    NSLog(@"PROBLEM - CONTACT NOT ADDED");
                }

我看到了"PROBLEM - CONTACT NOT ADDED"消息。

任何帮助？

Answer 1

问题是您要在NSDocumentationDirectory而不是NSDocumentDirectory中打开数据库。

几个不相关的观察结果：

如果sqlite3_open()失败，您应该查看数字返回代码，它将帮助您诊断问题的根源。您可以在sqlite3.h标题文件中查找值。
对您的代码示例无关的观察：您应该检查sqlite3_prepare_v2()返回代码，因为通常会在那里识别SQL错误，而不是sqlite3_step()。如果它返回SQLITE_OK以外的内容，则立即致电sqlite3_errmsg()以确定其失败原因。
您不应使用stringWithFormat为INSERT SQL语句添加值。相反，使用?占位符，然后使用sqlite3_bind_XXX()函数将值绑定到这些SQL值。实际上，如果任何插入的值包含引号，则SQL将失败（并且容易受到SQL注入攻击）。

Answer 2

你犯了一个小错误，如@Rob所示......

而不是

dirPaths=NSSearchPathForDirectoriesInDomains(NSDocumentationDirectory, NSUserDomainMask, YES);

你应该使用

dirPaths=NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);

以下是更正后的代码，

NSString *docsDir;
NSArray *dirPaths;

dirPaths=NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
docsDir = [dirPaths objectAtIndex:0];
databasePath = [[NSString alloc] initWithString: [docsDir stringByAppendingPathComponent: @"contacts.db"]];

NSFileManager *filemgr=[NSFileManager defaultManager];

if ([filemgr fileExistsAtPath:databasePath]==NO)
{
    NSLog(@"Creating Database...");
    const char *dbpath=[databasePath UTF8String];

    if (sqlite3_open(dbpath, &contactDB)==SQLITE_OK)
    {
        char *error_msg;
        const char *sql_stmt = "CREATE TABLE IF NOT EXISTS CONTACTS (ID INTEGER PRIMARY KEY AUTOINCREMENT, URL TEXT, EMAIL TEXT, CODE TEXT, FULL TEXT)";

        if (sqlite3_exec(contactDB, sql_stmt, NULL, NULL, &error_msg) != SQLITE_OK)
        {
           NSLog(@"Failed to create table");
        }

        sqlite3_close(contactDB);

    } 
    else 
    {
        NSLog(@"Failed to open/create database");
    }
} 
else 
{
    NSLog(@"DB exists");
}

您可以插入这样的数据，

sqlite3_stmt *statement;

const char *dbpath = [databasePath UTF8String];

if (sqlite3_open(dbpath, &contactDB) == SQLITE_OK)
{
    NSString *insertSQL = [NSString stringWithFormat: @"INSERT INTO CONTACTS (url, email, code, full) VALUES (\"%@\", \"%@\", \"%@\", \"%@\")", url_2, mail, keycode,full_2 ];

    const char *insert_stmt = [insertSQL UTF8String];

    sqlite3_prepare_v2(contactDB, insert_stmt, -1, &statement, NULL);
    if (sqlite3_step(statement) == SQLITE_DONE)
    {
        NSLog(@"Contact added");
    } 
    else
    {
        NSLog(@"Failed to add contact");
    }
    sqlite3_finalize(statement);
    sqlite3_close(contactDB);
} 
else
{
    NSLog(@"PROBLEM - CONTACT NOT ADDED");
}

谢谢...... !!!

无法将数据添加到本地DB sqlite IOS

2 个答案: