How to Implement Full-Text Search in SQL Server

Full-text search in SQL Server allows for efficient searching of text data stored in tables. Unlike the traditional LIKE operator, full-text search enables powerful linguistic-based searches, ranking results by relevance and supporting advanced features like inflectional search and proximity queries. In this guide, we will walk through the steps to implement full-text search in SQL Server.

Before using full-text search, ensure that your SQL Server instance supports and has full-text search enabled. You can check this by running:

SELECT SERVERPROPERTY('IsFullTextInstalled') AS FullTextInstalled;

If the result is 1, full-text search is installed; otherwise, you may need to install it.

Step 2: Create a Full-Text Catalog

A full-text catalog is a container for full-text indexes. To create one, use:

CREATE FULLTEXT CATALOG MyFullTextCatalog AS DEFAULT;

Step 3: Create a Full-Text Index

A full-text index is required on the columns you want to search. First, make sure your table has a unique index:

CREATE UNIQUE INDEX UI_MyTable ON MyTable(Id);

Then, create a full-text index:

CREATE FULLTEXT INDEX ON MyTable(
    MyTextColumn LANGUAGE 1033
)
KEY INDEX UI_MyTable
ON MyFullTextCatalog;

The LANGUAGE 1033 specifies English. You can change this according to the language used in your data.

Step 4: Perform Full-Text Searches

Once the index is created, you can perform full-text searches using CONTAINS and FREETEXT.

Using CONTAINS

CONTAINS allows you to search for exact words or phrases:

SELECT * FROM MyTable
WHERE CONTAINS(MyTextColumn, '"search term"');

You can also use logical operators like AND, OR, and NEAR:

SELECT * FROM MyTable
WHERE CONTAINS(MyTextColumn, '"SQL Server" NEAR "Index"');

Using FREETEXT

FREETEXT allows for a broader, natural language search:

SELECT * FROM MyTable
WHERE FREETEXT(MyTextColumn, 'search term');
  • Populate the Full-Text Index: Full-text indexes are updated automatically, but you can manually trigger an update:

    ALTER FULLTEXT INDEX ON MyTable START FULL POPULATION;
    
  • Monitor Full-Text Indexing: Check the status of your full-text population with:

    SELECT * FROM sys.fulltext_indexes;
    
  • Remove a Full-Text Index: If needed, drop the index using:

    DROP FULLTEXT INDEX ON MyTable;
    

Conclusion

Full-text search in SQL Server is a powerful tool for handling complex text-based queries. By enabling full-text search, creating an index, and using CONTAINS or FREETEXT queries, you can significantly improve search performance and relevance in your applications. With proper indexing and management, full-text search can be a game-changer for handling large text-based datasets.

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Related

String interpolation, introduced in C# 6.0, provides a more readable and concise way to format strings compared to traditional concatenation (+) or string.Format(). Instead of manually inserting variables or placeholders, you can use the $ symbol before a string to directly embed expressions inside brackets.

string name = "Walt";
string job = 'Software Engineer';

string message = $"Hello, my name is {name} and I am a {job}";
Console.WriteLine(message);

This would produce the final output of:

Hello, my name is Walt and I am a Software Engineer

String interpolation can also be chained together into a multiline string (@) for even cleaner more concise results:

string name = "Walt";
string html = $@"
    <div>
        <h1>Welcome, {name}!</h1>
    </div>";
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Closing a SqlDataReader correctly prevents memory leaks, connection issues, and unclosed resources. Here’s the best way to do it.

Use 'using' to Auto-Close

Using using statements ensures SqlDataReader and SqlConnection are closed even if an exception occurs.

Example

using (SqlConnection conn = new SqlConnection(connectionString))
{
    conn.Open();
    using (SqlCommand cmd = new SqlCommand("SELECT * FROM Users", conn))
    using (SqlDataReader reader = cmd.ExecuteReader())
    {
        while (reader.Read())
        {
            Console.WriteLine(reader["Username"]);
        }
    } // ✅ Auto-closes reader here
} // ✅ Auto-closes connection here

This approach auto-closes resources when done and it is cleaner and less error-prone than manual closing.

⚡ Alternative: Manually Close in finally Block

If you need explicit control, you can manually close it inside a finally block.

SqlDataReader? reader = null;
try
{
    using SqlConnection conn = new SqlConnection(connectionString);
    conn.Open();
    using SqlCommand cmd = new SqlCommand("SELECT * FROM Users", conn);
    reader = cmd.ExecuteReader();

    while (reader.Read())
    {
        Console.WriteLine(reader["Username"]);
    }
}
finally
{
    reader?.Close();  // ✅ Closes reader if it was opened
}

This is slightly more error prone if you forget to add a finally block. But might make sense when you need to handle the reader separately from the command or connection.

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When working with URLs in C#, encoding is essential to ensure that special characters (like spaces, ?, &, and =) don’t break the URL structure. The recommended way to encode a string for a URL is by using Uri.EscapeDataString(), which converts unsafe characters into their percent-encoded equivalents.

string rawText = "hello world!";
string encodedText = Uri.EscapeDataString(rawText);

Console.WriteLine(encodedText); // Output: hello%20world%21

This method encodes spaces as %20, making it ideal for query parameters.

For ASP.NET applications, you can also use HttpUtility.UrlEncode() (from System.Web), which encodes spaces as +:

using System.Web;

string encodedText = HttpUtility.UrlEncode("hello world!");
Console.WriteLine(encodedText); // Output: hello+world%21

For .NET Core and later, Uri.EscapeDataString() is the preferred choice.

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