Resolve "Implement server-side cursors"

Closes #9 (closed)

\approve @gislars @ds

databaselib/database.py

@@ -21,6 +21,7 @@ import logging
 import sqlite3
 import psycopg2
 from packaging import version
+from uuid import uuid4
 
 
 logger = logging.getLogger()
@@ -245,3 +246,24 @@ class PostGISDatabase(AbstractDatabase):
             self.cursor = self.connection.cursor()
         except Exception as e:
             logger.exception(e)
+
+    def execute_server_side(self, sql_statement: str, itersize: int = None):
+        """
+        Execute an SQL statement with a server-side cursor.
+
+        Args:
+            sql_statement (str):
+                SQL statement to be executed.
+            itersize (int):
+                Number of rows fetched from the server at one call.
+
+        Returns:
+            Generator object of the query result.
+        """
+
+        with self.connection.cursor(name=f"{uuid4()}") as cursor:
+            if itersize is not None:
+                cursor.itersize = itersize
+            cursor.execute(sql_statement)
+            for result in cursor:
+                yield result