Staging.Staging-To-DimPeople_K12Students

Overview & Purpose

This stored procedure populates the RDS.DimPeople dimension table with K-12 student data from the Staging.K12Enrollment table. It handles the creation of new student records and manages the historization of student data by setting appropriate start and end dates.

Main Functions:

• Insert Default Record

  Ensures a default record with DimPersonId = -1 exists in the RDS.DimPeople table

• Student Data Extraction

  Extracts distinct student records from Staging.K12Enrollment into a temporary table

• MERGE Operation

  Inserts new student records into RDS.DimPeople that don't already exist

• Historical Record Management

  Updates end dates for previous records of the same student to maintain historical accuracy

Key Calculations:

• Historical Record Management: Calculates the end date for previous student records

  Formula: dateadd(day, -1, min(endd.RecordStartDateTime))

  Business Significance: Ensures historical tracking of student data changes over time

  Example: If a student has records starting on 2022-01-01 and 2022-06-01, the first record's end date would be set to 2022-05-31

Data Transformations:

• Extraction of distinct student demographic data from enrollment records

• Setting IsActiveK12Student flag to 1 for all extracted records

• Setting appropriate start and end dates for historical tracking

Expected Output:

Updated RDS.DimPeople table with current and historical K-12 student records, properly maintaining the timeline of student information changes

Business Context

System: K-12 Student Information System

Necessity: Maintains a dimensional model of student data for reporting and analysis purposes

Business Rules:

• Each student is uniquely identified by a combination of state ID, name, and birth date

• Historical changes to student records must be preserved with appropriate date ranges

• A default record with ID -1 must exist for referential integrity

Result Usage:

The dimension table is likely used for reporting, analytics, and data warehousing purposes related to K-12 education

Execution Frequency:

Likely executed on a regular schedule (daily, weekly, or monthly) or after K12Enrollment data is updated

Critical Periods:

• Beginning and end of school terms

• State reporting deadlines

Parameters

Parameter	Data Type	Purpose	Required
@dataCollectionId	INT	Likely intended to filter data by a specific collection ID, though not currently used in the procedure	False

Source Tables

Staging.K12Enrollment

Business Purpose: Stores K-12 student enrollment data in a staging area

Columns:

Name	Data Type	Business Purpose
FirstName	NVARCHAR	Student's first name
MiddleName	NVARCHAR	Student's middle name
LastOrSurname	NVARCHAR	Student's last name or surname
BirthDate	DATE	Student's date of birth
StudentIdentifierState	NVARCHAR	State-assigned student identifier
EnrollmentEntryDate	DATE	Date when student enrolled
EnrollmentExitDate	DATE	Date when student exited enrollment

Temporary Tables

#k12Students

Purpose: Temporary storage for distinct student records extracted from Staging.K12Enrollment

Columns:

Name	Data Type	Purpose/Calculation
FirstName	NVARCHAR(50)	Direct copy from source
MiddleName	NVARCHAR(50)	Direct copy from source
LastOrSurname	NVARCHAR(50)	Direct copy from source
BirthDate	DATE	Direct copy from source
K12StudentStudentIdentifierState	NVARCHAR(40)	Direct copy from StudentIdentifierState
IsActiveK12Student	BIT	Set to 1 for all records
RecordStartDateTime	DATE	Set to EnrollmentEntryDate
RecordEndDateTime	DATE	Set to EnrollmentExitDate

Potential Improvements

Error Handling

Description: Add more specific error handling for each major operation

Benefits: Better troubleshooting and more graceful failure handling

Priority: Medium

Performance

Description: Add appropriate indexes to the temporary table

Benefits: Faster MERGE operation, especially with large datasets

Priority: Medium

Functionality

Description: Implement the @dataCollectionId parameter functionality

Benefits: Allow filtering by data collection ID as intended

Priority: Low

Transaction Management

Description: Add explicit transaction control

Benefits: Ensure atomicity of operations

Priority: Medium

Execution Steps

Step 1: Ensure default record exists

Input Data: None

Transformations: None

IF NOT EXISTS (SELECT 1 FROM RDS.DimPeople WHERE DimPersonId = -1) BEGIN SET IDENTITY_INSERT RDS.DimPeople ON INSERT INTO RDS.DimPeople (DimPersonId) VALUES (-1) SET IDENTITY_INSERT RDS.DimPeople off END

Step 2: Create temporary table for student data

Input Data: None

Transformations: None

CREATE TABLE #k12Students (...)

Step 3: Extract distinct student records

Input Data: Staging.K12Enrollment

Transformations: Selection of specific columns, setting IsActiveK12Student to 1

INSERT INTO #k12Students (...) SELECT DISTINCT ... FROM Staging.K12Enrollment e

Step 4: Insert new student records

Input Data: #k12Students temporary table

Transformations: None

MERGE rds.DimPeople AS trgt USING #k12Students AS src ON ... WHEN NOT MATCHED BY TARGET THEN INSERT ...

Step 5: Update end dates for historical records

Input Data: RDS.DimPeople

Transformations: Calculate end dates for previous records

WITH upd AS (...) UPDATE student SET RecordEndDateTime = upd.RecordEndDateTime FROM rds.DimPeople student INNER JOIN upd ON ...