Generate CREATE TABLE statements from C# classes for SQL Server, MySQL, and PostgreSQL.
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The generator parses your classes, records and enums with a hand-written C# declaration parser — not Roslyn — and turns each class with public properties into one CREATE TABLE statement for the dialect you pick. Each property is mapped through a per-dialect type table, data annotations adjust the name, type, length and nullability, and anything that cannot be a single column (collections, dictionaries, navigation properties) is skipped with a warning under the output rather than silently dropped. Enums are stored as their underlying integer type, as EF Core does by default. The CREATE TABLE statements are generated in your browser.
string is NVARCHAR(255) on SQL Server, TEXT on PostgreSQL and VARCHAR(255) on MySQL unless [MaxLength] or [StringLength] gives a length. decimal is DECIMAL(18,2) (NUMERIC on PostgreSQL) unless [Precision] or [Column(TypeName)] says otherwise. DateTime is DATETIME2, TIMESTAMP or DATETIME; Guid is UNIQUEIDENTIFIER, UUID or CHAR(36); byte[] is VARBINARY(MAX), BYTEA or LONGBLOB.
[Key] first, then Id, then <ClassName>Id — the same conventions EF Core uses. Integer keys get the dialect's identity syntax: IDENTITY(1,1), GENERATED BY DEFAULT AS IDENTITY or AUTO_INCREMENT. Composite keys are not inferred.
A property whose type is another class, such as public Customer Customer, is skipped with a warning. Its foreign key column (CustomerId) is kept as an ordinary column, but no FOREIGN KEY constraint or index is written — add those yourself.
If the project already uses EF Core and the database is yours, use migrations. dotnet ef migrations add reads your DbContext, including Fluent API configuration, owned types, relationships and indexes, and it keeps a history you can roll back. This tool can't see any of that.
Where it earns its place is everywhere migrations don't reach: a DBA who wants a CREATE TABLE script to review before anything touches production, a Dapper or ADO.NET project with no DbContext, a quick SQLite or PostgreSQL table for a spike, or checking what types a DTO would need before you design the real schema. Paste the class, read the DDL, and edit it — it's a starting script, not a migration.
The prefilled Order class covers the cases that usually go wrong. [Precision(10, 2)] narrows Total to DECIMAL(10,2) while Discount keeps the (18,2) default; DateTime? ShippedAt becomes a NULL column; the OrderStatus enum becomes INT; CustomerId stays as a column while the Customer navigation property is skipped with a warning.
CREATE TABLE [orders] (
[Id] INT IDENTITY(1,1) PRIMARY KEY,
[Reference] NVARCHAR(32) NOT NULL,
[Notes] NVARCHAR(255) NULL,
[Total] DECIMAL(10,2) NOT NULL,
[Discount] DECIMAL(18,2) NULL,
[CreatedAt] DATETIME2 NOT NULL,
[ShippedAt] DATETIME2 NULL,
[Status] INT NOT NULL,
[CustomerId] UNIQUEIDENTIFIER NOT NULL
);Short answers for the things developers usually ask before trusting a tool.
SQL Server (T-SQL), PostgreSQL and MySQL. Identifiers are quoted per dialect ([brackets], "double quotes" or `backticks`) and each has its own type map — a string without a length is NVARCHAR(255) on SQL Server, TEXT on PostgreSQL and VARCHAR(255) on MySQL.
A property with [Key] wins; otherwise a property named Id, then one named <ClassName>Id, becomes the primary key. int and long keys get IDENTITY(1,1), GENERATED BY DEFAULT AS IDENTITY or AUTO_INCREMENT; a Guid key is a plain UNIQUEIDENTIFIER, UUID or CHAR(36) key with no database default, because EF Core generates Guid keys on the client.
Yes, following nullable reference types: int?, DateTime? and string? become NULL, while int, DateTime and string (without ?) become NOT NULL. [Required] forces NOT NULL even on a nullable type. If your project has nullable reference types turned off, add ? to the strings that may be null.
No. The class is parsed and the CREATE TABLE generated in your browser; it is not sent to a ByteKiln server. If you press Share, the link itself carries a readable copy of your input, so don't share links that contain secrets.
[Table("name")], [Key], [Column("name")], [Column(TypeName = "…")], [MaxLength(n)], [StringLength(n)], [Precision(p, s)], [Required] and [DefaultValue(x)]. [ForeignKey], [Index], [NotMapped] and Fluent API configuration in OnModelCreating are not read, because the tool only sees the class you paste.
Useful follow-ups when one conversion usually turns into three more.
Format raw SQL with dialect support for SQL Server, MySQL, PostgreSQL, SQLite, and more.
Run SQL queries against an in-browser SQLite database. Paste your schema, seed data, and query — instant results.
Turn CREATE TABLE statements from SQL Server, PostgreSQL, MySQL or SQLite into EF Core entity classes — data annotations, Fluent API, or plain POCOs.
Want the background and worked examples? There's a longer write-up.
Read the C# → SQL guide