Question

I have data structure something along the line of this –

class House
{
    int id;
    string street;
    string city;
    string review;
    string status;
}

1. street and city are regular strings and should always be less than 32 characters. I take it they should have an SQL data type of nchar(32)? Or should they be varchar?

2. review is an optional string that users may input. And if they do give it, it can vary hugely, from 4-5 words up to 2000+ characters. So what data type should I use to store this?

3. status is a flag that can have values of ‘New’, ‘Old’, ‘UnStarted’. Whatever value it has will be displayed in a datagrid in a desktop application. Should I be storing this field as a string, or a byte with different bits acting as flags?

Answer 1

I would suggest using VARCHAR(32) for address and city if you are designing a United States table. If you are designing an international one, make both fields larger and switch to NVARCHAR(72) for example. NVARCHAR storage takes up more space, but allows non-ASCII characters to be stored….

CHAR(32) reserves 32 bytes of data, regardless of whether the field holds 1 character or 32 characters. In addition, some client programming languages will not trim the extra spaces automatically (which is proper, but might not be expected). NCHAR(32) reserves 64 bytes, since every character is represent in 2 bytes

For the review, I agree with lanks, a TEXT or VARCHAR(max) –(MS SQL specific) would be best. Can the review be longer than 2000 characters? If 2000 is the absolute limit, then I would go with VARCHAR(2000). I would only go with a TEXT field if you can have any length review. Keep in mind, if a user enters a review more than 2000 characters, the database will raise an error if you try to insert it, so your application needs to either restrict the number of characters or handle the error when it occurs.

Status should be the smallest integer your database allows. You can create a second table to provide text descriptions for the codes.