C# Equivalent of the TINYINT Data Type in SQL

TINYINT is one of the simplest numeric data types you can ever work with in SQL databases. It stores small numeric values, saves space, and is commonly used for flags, statuses, and boolean-like fields. But the moment you bring C# into the picture, things get intriguing. There is no TINYINT keyword in C#, and no one-to-one mapping you can use. Instead, you are left asking an important question: What is the correct C# equivalent of the TINYINT data type in SQL? 

The right TINYINT equivalent in C# gives you cleaner code, safer data handling, and a much clearer connection between your application and the database. But the wrong one can cause subtle bugs, data loss, unnecessary casting, or performance issues that only surface under real-world loads. 

This guide explains what TINYINT really represents in SQL, how it behaves across common database systems, and which C# data types map to it most accurately. You’ll also learn when to use the C# equivalent of TINYINT and how to avoid the hidden pitfalls that catch even experienced developers off guard.  

Let’s get started.

• What is TINYINT in SQL?
• C# equivalent of TINYINT in SQL 
• C# equivalent of SQL Server data types
• Conclusion 

What is TINYINT in SQL? 

TINYINT is a numeric data type in SQL designed to store minimal integer values efficiently. It is primarily used to represent data that doesn’t require a large range of numbers, for example, flags, status codes, counters, and simple enumerations. With TINYINT, you can optimize table storage while accurately encoding small but meaningful logic directly in the database. 

Additionally, TINYINT typically occupies 1 byte, making it one of the most space-efficient numeric data types in SQL. This minimal storage ability is one of its biggest advantages in database development. However, the TINYINT numeric range depends on your database system: 

• In some systems, TINYINT stores only non-negative values.
• In others, it can be signed or unsigned, affecting whether it supports negative numbers.
• These differences are subtle but critical when mapping the data to C#. 

TINYINT comes in handy when you need to: 

• Represent boolean-like values (for example, 0 and 1)
• Store status indicators (active/inactive, pending/approved)
• Model small enums or codes with a limited number of states
• Optimize large tables where every byte of storage matters 

Now, because these values often control application behavior, choosing the correct TINYINT equivalent type in C# becomes especially important. Let’s go through TINYINT in different databases. 

TINYINT across SQL Server, MySQL, and PostgreSQL 

Here is how TINYINT differs across some database systems: 

• SQL Server 
  TINYINT is an unsigned 1-byte integer with a range of 0 to 255. It’s frequently used for flags and small numeric values.
• MySQL 
  TINYINT is also a 1-byte integer, but it is signed by default, with a range of -128 to 127. MySQL additionally supports TINYINT UNSIGNED, which expands the range to 0 to 255.
• PostgreSQL 
  PostgreSQL does not support TINYINT at all. Instead, you’ll opt for SMALLINT, which occupies more storage and supports a much wider range of values. 

These differences in how TINYINT is implemented across different databases explain why mapping TINYINT to C# isn’t as simple as picking a similar data type. More importantly, understanding how each database treats TINYINT is the basis for choosing the correct and safest C# equivalent. 

Now let’s get into the main discussion: what are the C# equivalents of TINYINT in SQL? 

C# equivalent of TINYINT in SQL 

In C#, the closest and most accurate equivalent of SQL’s TINYINT data type is the byte type. A byte occupies 1 byte of memory and supports values from 0 to 255, which perfectly aligns with how TINYINT behaves in SQL Server and with TINYINT UNSIGNED in MySQL. Also, byte makes the natural choice when you want a safe, efficient, and intention-revealing mapping between your database and application code. 

When a TINYINT column allows NULL values, the correct C# counterpart is byte? (nullable byte). This data type ensures that optional database values are handled correctly without resorting to sentinel values or hacks. 

Mapping TINYINT columns to C# properties 

Here’s a practical example demonstrating how to map TINYINT columns to C# properties in a typical entity class: 

public class UserAccount 
{ 
    public int Id { get; set; } 
     
    public string Username { get; set; } 
     
    // Maps to TINYINT - stores account status (0-255) 
    public byte Status { get; set; } 
     
    // Maps to nullable TINYINT - stores optional priority level 
    public byte? PriorityLevel { get; set; } 
     
    // Maps to TINYINT - stores age (0-255 is sufficient) 
    public byte Age { get; set; } 
     
    // Maps to TINYINT - boolean-like flag with multiple states 
    public byte NotificationPreference { get; set; } 
} 

Using byte makes the intent of your model clear: these values are small, bounded, and tightly coupled to the database representation. It also prevents invalid assignments that could otherwise sneak in if you used a larger data type like int. 

To improve readability and maintainability, it’s a good practice to define constants (or enums) for TINYINT-based status values: 

public static class AccountStatus 
{ 
    public const byte Inactive = 0; 
    public const byte Active = 1; 
    public const byte Suspended = 2; 
    public const byte Deleted = 3; 
} 
 
You can then create and use your entity like this: 
var user = new UserAccount 
{ 
    Username = "johndoe", 
    Status = AccountStatus.Active, 
    Age = 28, 
    PriorityLevel = null, // No priority assigned yet 
    NotificationPreference = 1 
}; 

This approach keeps your code expressive while maintaining a strict connection with the database. 

Mapping TINYINT with Entity Framework Core 

When working with Entity Framework Core, TINYINT columns are usually mapped to byte automatically. However, being explicit in your configuration can improve clarity and prevent provider-specific issues. Here is an example of how to do this: 

public class UserAccountConfiguration : IEntityTypeConfiguration<UserAccount> 
{ 
    public void Configure(EntityTypeBuilder<UserAccount> builder) 
    { 
        builder.Property(u => u.Status) 
            .HasColumnType("TINYINT") 
            .IsRequired(); 
             
        builder.Property(u => u.PriorityLevel) 
            .HasColumnType("TINYINT"); 
             
        builder.Property(u => u.Age) 
            .HasColumnType("TINYINT") 
            .IsRequired(); 
    } 
} 

Explicit mappings are especially useful when working across multiple database providers or when maintaining strict control over schema generation. 

Reading TINYINT values with ADO.NET 

For direct ADO.NET access, TINYINT values can be read safely using the GetByte method on a data reader: 

using (var connection = new SqlConnection(connectionString)) 
{ 
    var command = new SqlCommand("SELECT Status, Age FROM UserAccount WHERE Id = @Id", connection); 
    command.Parameters.AddWithValue("@Id", userId); 
     
    connection.Open(); 
    using (var reader = command.ExecuteReader()) 
    { 
        if (reader.Read()) 
        { 
            byte status = reader.GetByte(0);  // Reading TINYINT as byte 
            byte age = reader.GetByte(1); 
             
            Console.WriteLine($"Status: {status}, Age: {age}"); 
        } 
    } 
} 

This direct mapping avoids unnecessary conversions and ensures optimal performance. 

In summary, when working with SQL TINYINT, byte, and byte? are the correct, safest, and most intention-aligned choices in C#. Choosing them deliberately helps you avoid subtle bugs, improves code clarity, and keeps your data layer precise and predictable.

C# equivalent of SQL Server data types 

In SQL Server, when building applications that connect to C#, understanding how SQL Server data types map to C# types is essential for data accuracy, performance, and long-term maintainability. Although many mappings look intuitive at first glance, subtle differences in range, precision, nullability, and behavior can lead to bugs if overlooked. 

The table below provides a clear, practical reference for SQL Server–to–C# type conversion, highlighting the recommended C# type and important range or usage notes. 

SQL Server to C# type conversion table 

Important notes and best practices 

• Nullable columns 
  If an SQL Server column allows NULL, always use a nullable C# type (for example, int?, byte?, DateTime?) to preserve correct semantics.
• Modern date and time types 
  DateOnly and TimeOnly are available starting with .NET 6 and provide more precise, intention-revealing mappings for SQL Server DATE and TIME.
• Decimal precision awareness 
  SQL Server supports DECIMAL precision up to 38 digits, while C# decimal supports 28–29 significant digits. Be cautious when working with very high-precision values.
• String and Unicode handling 
  C# string maps to both Unicode (NVARCHAR, NCHAR) and non-Unicode (VARCHAR, CHAR) SQL types. Ensure your database collation and encoding match your application’s requirements.
• Avoid floating-point for money 
  Always map MONEY and SMALLMONEY to decimal in C# to prevent rounding and precision issues associated with floating-point types. 

Having a clear, reliable mapping between SQL Server and C# data types, especially small but critical ones like TINYINT, helps ensure your application remains robust, predictable, and free from hard-to-diagnose data bugs. 

Conclusion 

TINYINT may be one of the smallest data types in SQL Server, but its impact on your application can be significant. TINYINT is designed to store compact numeric values in the range of 0 to 255 and comes in handy for flags, statuses, and small enumerations. In C#, its true equivalent is the byte type or byte? for nullable columns. Both data types offer a precise, memory-efficient, and intention-aligned mapping between your database and application layers. 

Choosing the correct data type is more than a matter of convention; it directly affects data integrity, performance, and code clarity. Using a larger type like int where a byte is sufficient may seem harmless, but it can introduce unnecessary memory usage, weaken validation guarantees, and obscure the true meaning of your data. Accurate type mapping ensures that the rules enforced by your database are respected consistently in your C# code. 

As a final takeaway, always start your data modeling from the database schema and map types deliberately. Use nullable C# types for nullable columns, prefer byte over int for TINYINT, and be explicit in your ORM configurations when needed. Keep an eye on differences across database providers, and document the intent behind status and flag fields using constants or enums. These small, deliberate choices add up to cleaner code, fewer bugs, and a data layer you can trust.