adding employee hierarchy example

Author: Christy Cao

src/datacustomcode/templates/examples/employee_hierarchy/employee_data.csv

@@ -0,0 +1,13 @@
+id,name,position,manager_id
+1,Alice,CEO,
+2,Bob,VP Engineering,1
+3,Charlie,VP Sales,1
+4,David,Engineering Lead,2
+5,Eve,Engineering Lead,2
+6,Frank,Sales Manager,3
+7,Grace,Software Eng.,4
+8,Hannah,Software Eng.,4
+9,Ian,Software Eng.,5
+10,Jack,Sales Rep,6
+11,Kelly,Sales Rep,6
+12,Leo,Intern,7

src/datacustomcode/templates/examples/employee_hierarchy/entrypoint.py

@@ -0,0 +1,64 @@
+from pyspark.sql.functions import col, lit, concat_ws
+
+from datacustomcode.client import Client
+from datacustomcode.io.writer.base import WriteMode
+
+
+def main():
+    client = Client()
+
+    employees = client.read_dlo("Employee__dll").persist()
+    employees = employees.select(
+        "id__c",
+        "manager_id__c",
+        "name__c",
+        "position__c"
+    )
+    employees.show()
+    employees_with_manager = employees.alias("e") \
+        .join(employees.alias("m"), col("e.manager_id__c").cast("string") == col("m.id__c").cast("string"), "left") \
+        .select(
+            col("e.id__c"),
+            col("e.name__c"),
+            col("e.position__c"),
+            col("e.manager_id__c"),
+            col("m.name__c").alias("manager_name__c")
+        ).persist()
+
+    hierarchy_df = employees_with_manager.filter(col("manager_id__c").isNull()) \
+        .withColumn("hierarchy_level__c", lit(1)) \
+        .withColumn("management_chain__c", col("name__c")).persist()
+
+    current_level = 1
+
+    while True:
+        ewm = employees_with_manager.alias("ewm")
+        hdf = hierarchy_df.filter(col("hierarchy_level__c") == current_level).alias("hdf")
+
+        next_level_df = (ewm
+                         .join(hdf, col("ewm.manager_id__c").cast("string")  == col("hdf.id__c").cast("string") , "inner")
+                         .select(
+                             col("ewm.id__c"),
+                             col("ewm.name__c"),
+                             col("ewm.position__c"),
+                             col("ewm.manager_id__c"),
+                             col("ewm.manager_name__c"),
+                             (col("hdf.hierarchy_level__c") + 1).alias("hierarchy_level__c"),
+                             concat_ws(" | ", col("hdf.management_chain__c"), col("ewm.name__c")).alias("management_chain__c")
+                         )
+                        )
+
+        if next_level_df.isEmpty():
+            break
+
+        hierarchy_df = hierarchy_df.union(next_level_df).persist()
+        current_level += 1
+
+    hierarchy_df = hierarchy_df.orderBy("hierarchy_level__c", "manager_id__c", "id__c")
+
+    dlo_name = "Employee_Hierarchy__dll"
+    client.write_to_dlo(dlo_name, hierarchy_df, WriteMode.APPEND)
+
+
+if __name__ == "__main__":
+    main()