add stub of a dbml importer

Author: sierra-moxon

docs/packages/importers.rst

@@ -77,6 +77,13 @@ NCI implements a JSON serialization of ISO-11197. You can import this JSON and c
     schemauto import-cadsr "cdes/*.json"
 
 
+Importing from DBML
+--------------------
+
+DBML is a simple DSL for defining database schemas. It is a subset of SQL DDL.
+
+
+
 Packages for importing
 ----------------------  
 

poetry.lock

@@ -53,6 +53,7 @@ click-default-group = "^1.2.4"
 linkml-runtime = "^1.7.2"
 duckdb = "^0.10.1"
 numpy = "<2.0"
+pydbml = "^1.1.2"
 
 [tool.poetry.dev-dependencies]
 pytest = ">=7.1.1"

pyproject.toml

@@ -0,0 +1,98 @@
+from schema_automator.importers.import_engine import ImportEngine
+from pydbml import PyDBML
+from linkml_runtime.linkml_model import SchemaDefinition, ClassDefinition, SlotDefinition
+from dataclasses import dataclass
+
+@dataclass
+class DbmlImportEngine(ImportEngine):
+    """
+    An ImportEngine that introspects a DBML schema to determine a corresponding LinkML schema.
+    """
+
+    def convert(
+            self,
+            file: str,
+            name: str = None,
+            model_uri: str = None,
+            identifier: str = None,
+            **kwargs
+    ) -> SchemaDefinition:
+        """
+        Converts a DBML schema file into a LinkML SchemaDefinition.
+
+        :param file: Path to the DBML schema file.
+        :param name: Optional name for the generated LinkML schema.
+        :param model_uri: Optional URI for the schema.
+        :param identifier: Identifier field for the schema.
+        :return: SchemaDefinition object representing the DBML schema.
+        """
+        # Initialize the schema definition
+        schema_name = name or "GeneratedSchema"
+        schema = SchemaDefinition(name=schema_name, id=model_uri or f"https://example.org/{schema_name}")
+
+        # Parse the DBML file
+        with open(file, 'r', encoding='utf-8') as f:
+            dbml_content = f.read()
+        parsed_dbml = PyDBML(dbml_content)
+
+        # Process tables
+        for table in parsed_dbml.tables:
+            class_def = ClassDefinition(
+                name=table.name,
+                description=table.note or f"Auto-generated class for table '{table.name}'",
+                slots=[],
+                unique_keys=[],  # Initialize unique keys property
+            )
+            processed_slots = set()  # Track processed slot names to avoid duplicates
+
+            # Handle primary key and unique constraints
+            primary_key_columns = [col for col in table.columns if col.primary_key]
+            unique_columns = [col for col in table.columns if col.unique and not col.primary_key]
+            multi_column_unique_keys = table.indexes  # Assuming `indexes` captures multi-column unique keys
+
+            # Process columns
+            for column in table.columns:
+                slot_name = column.name
+                slot_def = SlotDefinition(
+                    name=slot_name,
+                    range=self._map_dbml_type_to_linkml(column.type),
+                    description=column.note or f"Column '{slot_name}'",
+                    required=column in primary_key_columns or column.unique,
+                    identifier=column in primary_key_columns,  # Mark primary key columns as identifiers
+                )
+                schema.slots[slot_name] = slot_def
+                class_def.slots.append(slot_name)
+                processed_slots.add(slot_name)
+
+            # Add multi-column unique keys
+            for index in multi_column_unique_keys:
+                if index.unique:
+                    class_def.unique_keys.append([col.name for col in index.columns])
+
+            # Handle single unique column as primary key if no explicit primary key exists
+            if not primary_key_columns and len(unique_columns) == 1:
+                unique_column = unique_columns[0]
+                schema.slots[unique_column.name].identifier = True
+                schema.slots[unique_column.name].required = True
+
+            schema.classes[table.name] = class_def
+
+        return schema
+
+    def _map_dbml_type_to_linkml(self, dbml_type: str) -> str:
+        """
+        Maps DBML data types to LinkML types.
+
+        :param dbml_type: The DBML column type.
+        :return: Corresponding LinkML type.
+        """
+        type_mapping = {
+            "int": "integer",
+            "varchar": "string",
+            "text": "string",
+            "float": "float",
+            "boolean": "boolean",
+            "date": "date",
+            "datetime": "datetime",
+        }
+        return type_mapping.get(dbml_type.lower(), "string")