How to Efficiently Insert Data into Parent and Child Tables Using a User-Defined Table Type in a Stored Procedure?

Efficiently Populating Parent and Child Tables within a Stored Procedure

This document outlines a solution for efficiently inserting data into parent and child tables within a stored procedure, leveraging a user-defined table type (UDT) for data input. The approach addresses the challenges of maintaining data integrity and avoiding performance bottlenecks associated with row-by-row operations.

The Challenge: Data Integrity and Performance

The challenge lies in accurately mapping data from a UDT to multiple related tables (a parent table and its associated child tables) within a stored procedure. Simple row-by-row inserts can be inefficient and prone to errors, especially when dealing with large datasets.

The Solution: A Multi-Step Approach

This solution employs a multi-step process to ensure both efficiency and data integrity:

1. Augmenting the UDT: Add a temporary ID column (temp_id) to the UDT. This serves as a unique identifier for each row within the UDT, crucial for tracking data across the insertion process.

2. Employing MERGE for Parent Table Insertion: The MERGE statement efficiently inserts data into the parent table (@MainEmployee). Critically, its OUTPUT clause captures both the temporary ID (temp_id from the UDT) and the newly generated EmployeeID from the parent table.

3. Creating a Mapping Table: The OUTPUT data from the MERGE statement populates a temporary mapping table (@EmployeeidMap). This table links the temporary temp_id to the actual EmployeeID generated in the parent table.

4. Parent Table Population with ID Mapping: The @EmployeeidMap table is then used to join the UDT data with the parent table (@ParentEmployeeDepartment), ensuring the correct EmployeeID is assigned to each parent record.

5. Child Table Population: Finally, the child tables (@ChildEmployeeDepartmentTypeA, @ChildEmployeeDepartmentTypeB) are populated using joins with both the @EmployeeidMap and @ParentEmployeeDepartment tables. This establishes the necessary relationships between parent and child records.

Illustrative Code Example:

The following code demonstrates this enhanced approach:

CREATE TYPE dbo.tEmployeeData AS TABLE 
(
     FirstName NVARCHAR(50),
     LastName NVARCHAR(50),
     DepartmentType NVARCHAR(10),
     DepartmentBuilding NVARCHAR(50),
     DepartmentEmployeeLevel NVARCHAR(10),
     DepartmentTypeAMetadata NVARCHAR(100),
     DepartmentTypeBMetadata NVARCHAR(100),
     temp_id INT IDENTITY(1,1) -- Added temporary ID column
)
GO

CREATE PROC dbo.EmployeeImport 
    (@tEmployeeData dbo.tEmployeeData READONLY)
AS
BEGIN
    -- ... (Temporary table declarations remain the same as in the original example) ...

    -- MERGE into @MainEmployee table
    MERGE INTO @MainEmployee USING @tEmployeeData AS sourceData ON 1 = 0
    WHEN NOT MATCHED THEN
        INSERT (FirstName, LastName)
        VALUES (sourceData.FirstName, sourceData.LastName)
    OUTPUT sourceData.temp_id, inserted.EmployeeID 
    INTO @EmployeeidMap;

    -- ... (Remaining INSERT statements adjusted to use @EmployeeidMap for joining) ...
END
GO

This refined strategy guarantees efficient and accurate data insertion, preserving referential integrity between parent and child tables while handling potentially large datasets effectively.

The above is the detailed content of How to Efficiently Insert Data into Parent and Child Tables Using a User-Defined Table Type in a Stored Procedure?. For more information, please follow other related articles on the PHP Chinese website!