refactor: move get_master regex to adapter methods

Each adapter now has its own get_master_table_name() method with a
backend-specific regex pattern:
- MySQL: matches backtick-quoted names
- PostgreSQL: matches double-quote-quoted names

Updated utils.get_master() to accept optional adapter parameter.
Updated table.py to pass adapter to get_master() calls.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: dimitri-yatsenko

src/datajoint/adapters/base.py

@@ -186,6 +186,24 @@ def quote_string(self, value: str) -> str:
         """
         ...
 
+    @abstractmethod
+    def get_master_table_name(self, part_table: str) -> str | None:
+        """
+        Extract master table name from a part table name.
+
+        Parameters
+        ----------
+        part_table : str
+            Full table name (e.g., `schema`.`master__part` for MySQL,
+            "schema"."master__part" for PostgreSQL).
+
+        Returns
+        -------
+        str or None
+            Master table name if part_table is a part table, None otherwise.
+        """
+        ...
+
     @property
     @abstractmethod
     def parameter_placeholder(self) -> str:

src/datajoint/adapters/mysql.py

@@ -221,6 +221,13 @@ def quote_string(self, value: str) -> str:
         escaped = client.converters.escape_string(value)
         return f"'{escaped}'"
 
+    def get_master_table_name(self, part_table: str) -> str | None:
+        """Extract master table name from part table (MySQL backtick format)."""
+        import re
+        # MySQL format: `schema`.`master__part`
+        match = re.match(r"(?P<master>`\w+`.`#?\w+)__\w+`", part_table)
+        return match["master"] + "`" if match else None
+
     @property
     def parameter_placeholder(self) -> str:
         """MySQL/pymysql uses %s placeholders."""

src/datajoint/adapters/postgres.py

@@ -238,6 +238,13 @@ def quote_string(self, value: str) -> str:
         escaped = value.replace("'", "''")
         return f"'{escaped}'"
 
+    def get_master_table_name(self, part_table: str) -> str | None:
+        """Extract master table name from part table (PostgreSQL double-quote format)."""
+        import re
+        # PostgreSQL format: "schema"."master__part"
+        match = re.match(r'(?P<master>"\w+"."#?\w+)__\w+"', part_table)
+        return match["master"] + '"' if match else None
+
     @property
     def parameter_placeholder(self) -> str:
         """PostgreSQL/psycopg2 uses %s placeholders."""

src/datajoint/table.py

@@ -953,7 +953,7 @@ def strip_quotes(s):
                     else:
                         child &= table.proj()
 
-                    master_name = get_master(child.full_table_name)
+                    master_name = get_master(child.full_table_name, table.connection.adapter)
                     if (
                         part_integrity == "cascade"
                         and master_name
@@ -1009,7 +1009,7 @@ def strip_quotes(s):
         if part_integrity == "enforce":
             # Avoid deleting from part before master (See issue #151)
             for part in deleted:
-                master = get_master(part)
+                master = get_master(part, self.connection.adapter)
                 if master and master not in deleted:
                     if transaction:
                         self.connection.cancel_transaction()
@@ -1100,7 +1100,7 @@ def drop(self, prompt: bool | None = None):
 
         # avoid dropping part tables without their masters: See issue #374
         for part in tables:
-            master = get_master(part)
+            master = get_master(part, self.connection.adapter)
             if master and master not in tables:
                 raise DataJointError(
                     "Attempt to drop part table {part} before dropping its master. Drop {master} first.".format(

src/datajoint/utils.py

@@ -25,23 +25,32 @@ def user_choice(prompt, choices=("yes", "no"), default=None):
     return response
 
 
-def get_master(full_table_name: str) -> str:
+def get_master(full_table_name: str, adapter=None) -> str:
     """
     If the table name is that of a part table, then return what the master table name would be.
     This follows DataJoint's table naming convention where a master and a part must be in the
     same schema and the part table is prefixed with the master table name + ``__``.
 
     Example:
-       `ephys`.`session`    -- master
-       `ephys`.`session__recording`  -- part
+       `ephys`.`session`    -- master (MySQL)
+       `ephys`.`session__recording`  -- part (MySQL)
+       "ephys"."session__recording"  -- part (PostgreSQL)
 
     :param full_table_name: Full table name including part.
     :type full_table_name: str
+    :param adapter: Optional database adapter for backend-specific parsing.
     :return: Supposed master full table name or empty string if not a part table name.
     :rtype: str
     """
-    match = re.match(r"(?P<master>`\w+`.`\w+)__(?P<part>\w+)`", full_table_name)
-    return match["master"] + "`" if match else ""
+    if adapter is not None:
+        result = adapter.get_master_table_name(full_table_name)
+        return result if result else ""
+
+    # Fallback: handle both MySQL backticks and PostgreSQL double quotes
+    match = re.match(r'(?P<master>(?P<q>[`"])[\w]+(?P=q)\.(?P=q)[\w]+)__[\w]+(?P=q)', full_table_name)
+    if match:
+        return match["master"] + match["q"]
+    return ""
 
 
 def is_camel_case(s):