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

Storing passwords as plain text is dangerous. Instead, you should hash them using a strong, slow hashing algorithm like BCrypt, which includes built-in salting and resistance to brute-force attacks.

Step 1: Install BCrypt NuGet Package

Before using BCrypt, install the BCrypt.Net-Next package:

dotnet add package BCrypt.Net-Next

or via NuGet Package Manager:

Install-Package BCrypt.Net-Next

Step 2: Hash a Password

Use BCrypt.HashPassword() to securely hash a password before storing it:

using BCrypt.Net;

string password = "mySecurePassword123";
string hashedPassword = BCrypt.HashPassword(password);

Console.WriteLine(hashedPassword); // Output: $2a$12$...

Step 3: Verify a Password

To check a user's login attempt, use BCrypt.Verify():

bool isMatch = BCrypt.Verify("mySecurePassword123", hashedPassword);
Console.WriteLine(isMatch); // Output: True

Ensuring proper hashing should be at the top of your list when it comes to building authentication systems.

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Primary constructors, introduced in C# 12, offer a more concise way to define class parameters and initialize fields.

This feature reduces boilerplate code and makes classes more readable.

Traditional Approach vs Primary Constructor

Before primary constructors, you would likely write something like the following:

public class UserService
{
    private readonly ILogger _logger;
    private readonly IUserRepository _repository;

    public UserService(ILogger logger, IUserRepository repository)
    {
        _logger = logger;
        _repository = repository;
    }

    public async Task<User> GetUserById(int id)
    {
        _logger.LogInformation("Fetching user {Id}", id);
        return await _repository.GetByIdAsync(id);
    }
}

With primary constructors, this becomes:

public class UserService(ILogger logger, IUserRepository repository)
{
    public async Task<User> GetUserById(int id)
    {
        logger.LogInformation("Fetching user {Id}", id);
        return await repository.GetByIdAsync(id);
    }
}

Key Benefits

  1. Reduced Boilerplate: No need to declare private fields and write constructor assignments
  2. Parameters Available Throughout: Constructor parameters are accessible in all instance methods
  3. Immutability by Default: Parameters are effectively readonly without explicit declaration

Real-World Example

Here's a practical example using primary constructors with dependency injection:

public class OrderProcessor(
    IOrderRepository orderRepo,
    IPaymentService paymentService,
    ILogger<OrderProcessor> logger)
{
    public async Task<OrderResult> ProcessOrder(Order order)
    {
        try
        {
            logger.LogInformation("Processing order {OrderId}", order.Id);
            
            var paymentResult = await paymentService.ProcessPayment(order.Payment);
            if (!paymentResult.Success)
            {
                return new OrderResult(false, "Payment failed");
            }

            await orderRepo.SaveOrder(order);
            return new OrderResult(true, "Order processed successfully");
        }
        catch (Exception ex)
        {
            logger.LogError(ex, "Failed to process order {OrderId}", order.Id);
            throw;
        }
    }
}

Tips and Best Practices

  1. Use primary constructors when the class primarily needs dependencies for its methods
  2. Combine with records for immutable data types:
public record Customer(string Name, string Email)
{
    public string FormattedEmail => $"{Name} <{Email}>";
}
  1. Consider traditional constructors for complex initialization logic

Primary constructors provide a cleaner, more maintainable way to write C# classes, especially when working with dependency injection and simple data objects.

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In C#, you can format an integer with commas (thousands separator) using ToString with a format specifier.

int number = 1234567;
string formattedNumber = number.ToString("N0"); // "1,234,567"
Console.WriteLine(formattedNumber);

Explanation:

"N0": The "N" format specifier stands for Number, and "0" means no decimal places. The output depends on the culture settings, so in regions where , is the decimal separator, you might get 1.234.567.

Alternative:

You can also specify culture explicitly if you need a specific format:

using System.Globalization;

int number = 1234567;
string formattedNumber = number.ToString("N0", CultureInfo.InvariantCulture);
Console.WriteLine(formattedNumber); // "1,234,567"
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