Generate SQL

SQL generation validates and maps a document, then renders it for a registered dialect. It does not require a live database or an installed ADO.NET provider.

From the command line

duburl schema render schema.yaml --dialect pgsql --output schema.sql

Without --output, SQL is written to standard output. Use duburl capabilities --json to discover renderable dialect aliases. Review the generated SQL before deployment.

Read, validate, map, and render in .NET

SchemaDocumentReader infers JSON from .json and YAML from .yaml or .yml. It requires an explicit supported version, rejects unknown properties, reports malformed input with source and location information, and leaves caller-owned streams open.

using DubUrl.Schema;
using DubUrl.Schema.Documents;
using DubUrl.Querying.Dialects;
using DubUrl.Provider.PostgreSql.Sql;

var reader = new SchemaDocumentReader();
var document = reader.Read("schema.yaml");

var validator = new SchemaDocumentValidator();
var diagnostics = validator.Validate(document);
var errors = diagnostics
    .Where(item => item.Severity == SchemaDocumentDiagnosticSeverity.Error)
    .ToArray();

if (errors.Length > 0)
    throw new InvalidOperationException(string.Join(
        Environment.NewLine,
        errors.Select(item => $"{item.Code} at {item.Path}: {item.Message}")));

var schema = new SchemaDocumentMapper(validator).Map(document);

var dialects = new DialectRegistryBuilder();
dialects.AddDialect<PgsqlDialect>(["pgsql"]);
var sql = new SchemaScriptRenderer(dialects.Build().Get<PgsqlDialect>()).Render(schema);

Validation accumulates diagnostics without mutating the DTO. Each diagnostic has a stable SDVnnn code, severity, message, and document path. SchemaDocumentMapper always validates before mapping and throws SchemaDocumentMappingException with all error diagnostics when the document is invalid, so explicit validation is optional when the caller does not need to present errors separately.

For a stream, specify the format and optionally a source name:

var document = reader.Read(stream, SchemaDocumentFormat.Yaml, "embedded-schema.yaml");

Render the lifecycle

The following example uses a runtime schema built with the C# schema builders.

var dialects = new DialectRegistryBuilder();
dialects.AddDialect<PgsqlDialect>(["pgsql"]);

var renderer = new SchemaScriptRenderer(
    dialects.Build().Get<PgsqlDialect>(),
    SchemaCreationOptions.DropIfExists);

var sql = renderer.Render(schema);

Creation renders tables and their constraints first, followed by deferred foreign keys, comments, indexes, and dependency-ordered views. With DropIfExists, dependent views are dropped first, then indexes, then tables. This ordering prevents the generated teardown from removing a source before its dependants.

Provider capabilities still apply. The renderer throws when the selected dialect cannot faithfully represent a requested identity, generated-column storage mode, regular-expression check, view, native type, or function.

For a portable JSON or YAML representation of the same model, see Schema documents.