Question

I have a user table with a single column for a person’s name:

CREATE TABLE [dbo].[Users]
(
    Id bigint NOT NULL,
    Name nvarchar(80) NOT NULL,
    PRIMARY KEY CLUSTERED (Id ASC)
)

The Name column can contain either a full name or just the first name or anything really (separated by spaces). In order to implement a search on Name, I would like to utilize SQL’s full-text search, but not sure if it’s suitable for searching names/nicknames and not actual words. Also the question is – which language do I choose when creating the FT index on Name?

Any other considerations?

Thank you.

Answer 1

It seems that if you want to search multi-part names, full-text search is the easiest and most appropriate approach (please correct me if I’m wrong). The other alternative being LIKE '%query%', however it has too many disadvantages:

• Terrible performance, since it does index scan
• Order of terms matters, e.g. – searching for “John Smith” and “Smith John” will return different results.
• It disregards word boundaries, e.g. – searching for “Ann” will also retrieve “Joanna” and “Danny”, which aren’t useful matches.

So I went ahead and implemented a full-text search. My queries look something like this:

SELECT * FROM Users WHERE CONTAINS(Name, '"John*"')

The only slight difficulty is that I had to convert user query (John) into a CONTAINS-friendly query (“John*”). To do that, I implemented this method in my UserRepository:

/// <summary>
/// Converts user-entered search query into a query that can be consumed by CONTAINS keyword of SQL Server.
/// </summary>
/// <example>If query is "John S Ju", the result will be "\"John*\" AND \"S*\" AND \"Ju*\"".</example>
/// <param name="query">Query entered by user.</param>
/// <returns>String instance.</returns>
public static string GetContainsQuery(string query)
{
    string containsQuery = string.Empty;

    var terms = query.Split(new[] { ' ' }, StringSplitOptions.None);

    if (terms.Length > 1)
    {
        for (int i = 0; i < terms.Length; i++)
        {
            string term = terms[i].Trim();

            // Add wildcard term, e.g. - "term*". The reason to add wildcard is because we want
            // to allow search by partially entered name parts (partially entered first name and/or
            // partially entered last name, etc).
            containsQuery += "\"" + term + "*\"";

            // If it's not the last term.
            if (i < terms.Length - 1)
            {
                // We want all terms inside user query to match.
                containsQuery += " AND ";
            }
        }

        containsQuery = containsQuery.Trim();
    }
    else
    {
        containsQuery = "\"" + query + "*\"";
    }

    return containsQuery;
}

Hope this helps anyone stumbling into the same issue.

PS – I wrote a blogpost documenting this.