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在我的视图控制器中，它显示了完整的细节。所以当用户点击添加按钮时，它会将数据插入到 sqlite。问题是如何检查之前是否插入了数据。

 //this code is in viewDidLoad
NSString *sql = [NSString stringWithFormat:@"SELECT * FROM exhibitor"];
    sqlite3_stmt *statement;
     check= 0;
    if(sqlite3_prepare_v2(db, [sql UTF8String], -1, &statement, nil) == SQLITE_OK){
        while (sqlite3_step(statement)==SQLITE_ROW) {
            char *exName2 = (char *) sqlite3_column_text(statement, 1);
            NSString *exNameStr = [[NSString alloc] initWithUTF8String:exName2];
            NSString *exhibName = [exhibitionArticle objectForKey:@"ex_name"];

            if([exNameStr isEqualToString:(exhibName)] ){
                check += 1;      
            }else{
                check += 0;
            }

        }
        NSLog(@"%d Result is", check);
    }     //this code checking my data is in sqlite or not

如果数据不在 sqlite 中，则按钮插入数据。

- (IBAction)addExhibitor:(id)sender {

    NSLog(@"%d this is addExhibitor int", check);
    if(check == 0){
    NSDate *exhibAddDate = [NSDate date];
    NSString *exhibName = [exhibitionArticle objectForKey:@"ex_name"];
    NSString *exhibAbout = [exhibitionArticle objectForKey:@"ex_about"];
    NSString *exhibBooth = [exhibitionArticle objectForKey:@"ex_booth"];
    NSString *exhibAddress = [exhibitionArticle objectForKey:@"ex_address"];
    NSString *exhibTelephone = [exhibitionArticle objectForKey:@"ex_telephone"];
    NSString *exhibFax = [exhibitionArticle objectForKey:@"ex_fax"];
    NSString *exhibWebSite = [exhibitionArticle objectForKey:@"ex_website"];
    NSString *exhibEmail = [exhibitionArticle objectForKey:@"ex_email"];

    NSString *sql1 = [NSString stringWithFormat:@"INSERT INTO exhibitor ('exhibAddDate', 'exhibName', 'exhibAbout', 'exhibBooth', 'exhibAddress', 'exhibTelephone', 'exhibFax', 'exhibWebSite', 'exhibEmail') VALUES('%@', '%@', '%@', '%@', '%@', '%@', '%@', '%@', '%@')", exhibAddDate, exhibName, exhibAbout, exhibBooth, exhibAddress, exhibTelephone, exhibFax, exhibWebSite, exhibEmail ];

    char *err;
    if(sqlite3_exec(db, [sql1 UTF8String], NULL, NULL, &err) != SQLITE_OK){

        sqlite3_close(db);
        NSAssert(0, @"Could not update table");
    }else{

        NSLog(@"Table Updated");
    }
    }
    else{
     //   UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Same Data" message:@"Your data already there" delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil, nil];
      //  [alert show];

    }


}
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1 回答 1

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int check = 0;
sqlite3_stmt *statement = nil;
const char * sql;

sql = "SELECT COUNT(*) FROM exhibitor WHERE exhibName = ?";

sqlite3_prepare_v2(db, sql, -1, &statement, NULL);
sqlite3_bind_text(statement, 1, [[exhibitionArticle objectForKey:@"ex_name"] UTF8String], -1, SQLITE_TRANSIENT);

while (sqlite3_step(statement) == SQLITE_ROW) {

    check = sqlite3_column_int(statement, 0);

}

sqlite3_finalize(statement);

if (check == 0) {
    NSLog(@"Result of count is %d and so the data is not in the database", check);
    //insert the data

    NSDate *exhibAddDate = [NSDate date];
    NSString *exhibName = [exhibitionArticle objectForKey:@"ex_name"];
    NSString *exhibAbout = [exhibitionArticle objectForKey:@"ex_about"];
    NSString *exhibBooth = [exhibitionArticle objectForKey:@"ex_booth"];
    NSString *exhibAddress = [exhibitionArticle objectForKey:@"ex_address"];
    NSString *exhibTelephone = [exhibitionArticle objectForKey:@"ex_telephone"];
    NSString *exhibFax = [exhibitionArticle objectForKey:@"ex_fax"];
    NSString *exhibWebSite = [exhibitionArticle objectForKey:@"ex_website"];
    NSString *exhibEmail = [exhibitionArticle objectForKey:@"ex_email"];

    sql = "INSERT INTO exhibitor ('exhibAddDate', 'exhibName', 'exhibAbout', 'exhibBooth', 'exhibAddress', 'exhibTelephone', 'exhibFax', 'exhibWebSite', 'exhibEmail') VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)";

    sqlite3_prepare_v2(db, sql, -1, &statement, NULL);
    sqlite3_bind_text(statement, 1, [exhibAddDate UTF8String], -1, SQLITE_TRANSIENT);
    sqlite3_bind_text(statement, 2, [exhibName UTF8String], -1, SQLITE_TRANSIENT);
    sqlite3_bind_text(statement, 3, [exhibAbout UTF8String], -1, SQLITE_TRANSIENT);
    sqlite3_bind_text(statement, 4, [exhibBooth UTF8String], -1, SQLITE_TRANSIENT);
    sqlite3_bind_text(statement, 5, [exhibAddress UTF8String], -1, SQLITE_TRANSIENT);
    sqlite3_bind_text(statement, 6, [exhibTelephone UTF8String], -1, SQLITE_TRANSIENT);
    sqlite3_bind_text(statement, 7, [exhibFax UTF8String], -1, SQLITE_TRANSIENT);
    sqlite3_bind_text(statement, 8, [exhibWebSite UTF8String], -1, SQLITE_TRANSIENT);
    sqlite3_bind_text(statement, 9, [exhibEmail UTF8String], -1, SQLITE_TRANSIENT);

    if (sqlite3_step(statement) == SQLITE_DONE){
         NSLog(@"Exhibit added");
    } else {
         NSLog( @"Failed from sqlite3_prepare_v2. Error is:  %s", sqlite3_errmsg(db));
    }

} else {
    NSLog(@"Result of count is %d and so the data is already in the database", check);
}

sqlite3_finalize(statement);
sqlite3_close(db);

试试这样的东西！

--> exhibName <-- sql中的必须是要搜索数据的列。

最好是把这一切都放在你拥有的 IBAction 中。如果检查 == 0，则执行插入。

请查看绑定变量，因为您容易受到 sql 注入的影响。这意味着，如果我输入诸如“blabla; DELETE * FROM existor; blabla”作为标题，您将面临用户删除表中所有数据的风险！绑定变量确保不会发生这种情况。

周围没有 XCode，所以我无法检查它是否一切正常.. 否则摆弄直到你拥有它！

祝你好运

于 2012-12-20T02:43:17.173 回答