[Mugala]

No, you don't need 3 dimensional array, also, there is a wrong placement in your code.
I suggest to use something like that

PHP Code:

enum VEHICLE_DATA
{
    vModel,
    vOwner[MAX_PLAYER_NAME+1],
    vOwnable,
    vType,
    vFaction,
    Float:vPos[4],
    vColor1,
    vColor2 //and so on...
};
new VehicleData[MAX_VEHICLES][VEHICLE_DATA];
public OnPlayerEnterVehicle(playerid, vehicleid, ispassenger) //example
{
    if(VehicleData[vehicleid][vOwnable]) //if 1 = ownable, if 0 = not ownable.
    {
         new str[128];
         format(str,sizeof(str),"Vehicle owner is %s",VehicleData[vehicleid][vOwner]);
         SendClientMessage(playerid,-1,str);
    }
    return 1;
} 


in a gamemodeinit (or vehicle load func) make only not-ownable vehicles loadable.

PHP Code:

public OnGameModeInit()
{
    mysql_tquery(handle,"SELECT * FROM `vehicles` WHERE `Ownable` != 1","LoadVehicles"); //example for last mysql plugin
    return 1;
}
forward LoadVehicles();
public LoadVehicles()
{
    new rows, total = 0;
    rows = cache_num_rows();
    if(rows > 0)
    {
        for(new i; i < rows; i++)
        {
            cache_get_value_name_int(i, "Model", VehicleData[i][vModel]);
            cache_get_value_name_int(i, "Color1", VehicleData[i][vColor1]);
            cache_get_value_name_int(i, "Color2", VehicleData[i][vColor2]);
            cache_get_value_name_int(i, "Type", VehicleData[i][vType]); //by type, you can access various things
            cache_get_value_name_int(i, "Faction", VehicleData[i][vFaction]); //if a vehicle is owned by a faction, faction ID can be placed here.
            cache_get_value_name_int(i, "PosX", VehicleData[i][vPos[0]]);
            cache_get_value_name_int(i, "PosY", VehicleData[i][vPos[1]]);
            cache_get_value_name_int(i, "PosZ", VehicleData[i][vPos[2]]);
            cache_get_value_name_int(i, "PosA", VehicleData[i][vPos[3]]);
   
            CreateVehicle(VehicleData[i][vModel],VehicleData[i][vPos[0]],VehicleData[i][vPos[1]],VehicleData[i][vPos[2]],VehicleData[i][vPos[3]],VehicleData[i][vColor1],VehicleData[i][vColor2],900);
        
            total++;
        }
        printf("Loaded %i vehicles from %i",total,rows);
    }
    return 1;
} 


so, for a player, make a dialog to choose which vehicle he wants to be loaded/spawned or you can make it with mSelection (list of a cars)

so, list of the player's cars can be obtained like this

PHP Code:

new name[MAX_PLAYER_NAME+1], query[128];
GetPlayerName(playerid,name,sizeof(name));
mysql_format(handler, query, sizeof(query), "SELECT * FROM `vehicles` WHERE `Owner` = '%e'",name);
new Cache:result = mysql_query(handle,query,true);
new rows = cache_num_rows();
if(rows > 0)
{
    new str[256];
    str = "ID\tModel"
    for(new i; i < rows; i++)
    {
        new temp[2];
        cache_get_value_name_int(i,"ID",temp[0]);
        cache_get_value_name_int(i,"Model",temp[1]);
        format(str,sizeof(str),"%s\n%i\t%i",str,temp[0],temp[1]);//you can also display a Model by its name, if you have a custom function for that.
    }
    ShowPlayerDialog(playerid,1234, DIALOG_STYLE_TABLIST_HEADERS, "Your Vehicles", str, "Select" , "Close");
}
else SendClientMessage(playerid,-1,"You don't own a vehicle");
cache_delete(result); 


loading can be similar, like first one, but now query must be like that

PHP Code:

new query[256],name[MAX_PLAYER_NAME+1];
GetPlayerName(playerid,name,sizeof(name));
mysql_format(handle,query,sizeof(query),"SELECT * FROM `vehicles` WHERE `Ownable` = '1' AND `Owner` = '%s'",name);