find and exit methods in tables

Exist Method:
static boolean exist(ItemId  itemId)--->this is key which is primary
{
    return itemId && (select RecId from inventTable -->table name
                index hint ItemIdx--->index name in table
                where inventTable.ItemId == itemId
                ).RecId != 0;
}
Find Method:
static InventTable find(ItemId      itemId,
                        boolean    update = false--->to define how many primarykeys in table )
{
    InventTable  inventTable;
    ;
    inventTable.selectForUpdate(update);
    if (itemId)
    {
        select firstonly inventTable-->table name
            index hint ItemIdx-->index name
            where inventTable.ItemId == itemId;
    }
    return inventTable;
}