Feat: sqlite primary key transforms closes #1557

sqlglot/dialects/sqlite.py

@@ -22,6 +22,40 @@ def _date_add_sql(self, expression):
     return self.func("DATE", expression.this, modifier)
 
 
+def _transform_create(expression: exp.Expression) -> exp.Expression:
+    """Move primary key to a column and enforce auto_increment on primary keys."""
+    schema = expression.this
+
+    if isinstance(expression, exp.Create) and isinstance(schema, exp.Schema):
+        defs = {}
+        primary_key = None
+
+        for e in schema.expressions:
+            if isinstance(e, exp.ColumnDef):
+                defs[e.name] = e
+            elif isinstance(e, exp.PrimaryKey):
+                primary_key = e
+
+        if primary_key and len(primary_key.expressions) == 1:
+            column = defs[primary_key.expressions[0].name]
+            column.append(
+                "constraints", exp.ColumnConstraint(kind=exp.PrimaryKeyColumnConstraint())
+            )
+            schema.expressions.remove(primary_key)
+        else:
+            for column in defs.values():
+                auto_increment = None
+                for constraint in column.constraints.copy():
+                    if isinstance(constraint.kind, exp.PrimaryKeyColumnConstraint):
+                        break
+                    if isinstance(constraint.kind, exp.AutoIncrementColumnConstraint):
+                        auto_increment = constraint
+                if auto_increment:
+                    column.constraints.remove(auto_increment)
+
+    return expression
+
+
 class SQLite(Dialect):
     class Tokenizer(tokens.Tokenizer):
         IDENTIFIERS = ['"', ("[", "]"), "`"]
@@ -66,6 +100,7 @@ class Generator(generator.Generator):
         TRANSFORMS = {
             **generator.Generator.TRANSFORMS,  # type: ignore
             exp.CountIf: count_if_to_sum,
+            exp.Create: transforms.preprocess([_transform_create]),
             exp.CurrentDate: lambda *_: "CURRENT_DATE",
             exp.CurrentTime: lambda *_: "CURRENT_TIME",
             exp.CurrentTimestamp: lambda *_: "CURRENT_TIMESTAMP",

sqlglot/expressions.py

@@ -1083,6 +1083,10 @@ class ColumnDef(Expression):
         "position": False,
     }
 
+    @property
+    def constraints(self) -> t.List[ColumnConstraint]:
+        return self.args.get("constraints") or []
+
 
 class AlterColumn(Expression):
     arg_types = {
@@ -1110,6 +1114,10 @@ class Comment(Expression):
 class ColumnConstraint(Expression):
     arg_types = {"this": False, "kind": True}
 
+    @property
+    def kind(self) -> ColumnConstraintKind:
+        return self.args["kind"]
+
 
 class ColumnConstraintKind(Expression):
     pass

tests/dialects/test_mysql.py

@@ -25,6 +25,19 @@ def test_ddl(self):
             "INSERT INTO x VALUES (1, 'a', 2.0) ON DUPLICATE KEY UPDATE SET x.id = 1"
         )
 
+        self.validate_all(
+            "CREATE TABLE x (id int not null auto_increment, primary key (id))",
+            write={
+                "sqlite": "CREATE TABLE x (id INTEGER NOT NULL AUTOINCREMENT PRIMARY KEY)",
+            },
+        )
+        self.validate_all(
+            "CREATE TABLE x (id int not null auto_increment)",
+            write={
+                "sqlite": "CREATE TABLE x (id INTEGER NOT NULL)",
+            },
+        )
+
     def test_identity(self):
         self.validate_identity("SELECT CURRENT_TIMESTAMP(6)")
         self.validate_identity("x ->> '$.name'")