Bulk Operations in Proc*C

Bulk operations in Proc*C allow you to manipulate multiple rows of data in a single operation, optimizing the efficiency and performance of database-centric C applications. These operations are particularly useful when you need to process large volumes of data efficiently. In this tutorial, we will explore the concept of bulk operations in Proc*C, provide examples, and explain the steps to effectively use bulk operations for data manipulation tasks.

1. Introduction to Bulk Operations

Traditional SQL operations work with single rows of data at a time, which can lead to increased network overhead and reduced performance when dealing with large datasets. Bulk operations, on the other hand, allow you to process multiple rows of data in a single operation, significantly reducing the number of interactions with the database server. This leads to improved performance and reduced execution time for data manipulation tasks.

2. Performing Bulk Insert

To perform a bulk insert in Proc*C, you can use the EXEC SQL FOR statement along with array handling. Let's take an example of bulk insert to insert multiple employee records into the employees table:

      /* EXEC SQL BEGIN DECLARE SECTION; */
      struct {
        int employee_id;
        char employee_name[50];
        float salary;
      } employees[10]; // Define an array to hold multiple employee records
      /* EXEC SQL END DECLARE SECTION; */
  // Initialize the array with employee data
  employees[0].employee_id = 1001;
  strcpy(employees[0].employee_name, "John");
  employees[0].salary = 50000;

  employees[1].employee_id = 1002;
  strcpy(employees[1].employee_name, "Jane");
  employees[1].salary = 60000;

  // ...

  /* EXEC SQL FOR :i = 0 TO 9
         INSERT INTO employees (employee_id, employee_name, salary)
         VALUES (:employees[i].employee_id, :employees[i].employee_name, :employees[i].salary);
  END FOR;
  END-EXEC; */

In this example, we define a structure employees to hold multiple employee records in an array. We then initialize the array with employee data. The EXEC SQL FOR statement is used to loop through the array and perform bulk insert into the employees table.

3. Performing Bulk Update

Similar to bulk insert, you can perform bulk updates in Proc*C using the EXEC SQL FOR statement along with array handling. Let's take an example of bulk update to update salaries of multiple employees in the employees table:

      /* EXEC SQL BEGIN DECLARE SECTION; */
      struct {
        int employee_id;
        float salary;
      } employees[10]; // Define an array to hold employee IDs and their updated salaries
      /* EXEC SQL END DECLARE SECTION; */
  // Initialize the array with employee IDs and their updated salaries
  employees[0].employee_id = 1001;
  employees[0].salary = 55000;

  employees[1].employee_id = 1002;
  employees[1].salary = 65000;

  // ...

  /* EXEC SQL FOR :i = 0 TO 9
         UPDATE employees SET salary = :employees[i].salary
         WHERE employee_id = :employees[i].employee_id;
  END FOR;
  END-EXEC; */

In this example, we define a structure employees to hold employee IDs and their updated salaries in an array. We then initialize the array with employee data. The EXEC SQL FOR statement is used to loop through the array and perform bulk updates in the employees table.

4. Common Mistakes with Bulk Operations

• Not properly initializing the array before performing bulk operations.
• Using incorrect data types or mismatching data types between the array and the database table.
• Not handling exceptions or errors that may occur during bulk operations.

5. Frequently Asked Questions (FAQs)

• Q: Can I use bulk operations with dynamic SQL statements?
  A: Yes, you can use bulk operations with both static and dynamic SQL statements in Proc*C.
• Q: Are there any limitations on the number of rows that can be processed in bulk operations?
  A: The number of rows that can be processed in a single bulk operation may vary depending on the database and system resources. It is recommended to perform performance testing to determine the optimal batch size for bulk operations.
• Q: Can I perform bulk operations on multiple tables in a single operation?
  A: No, bulk operations are typically performed on a single table at a time.
• Q: How do I handle errors during bulk operations?
  A: You can use exception handling in Proc*C to catch and handle errors that may occur during bulk operations.
• Q: Can I use bulk operations with non-sequential data in the array?
  A: Yes, you can use bulk operations with non-sequential data in the array. However, it is essential to ensure that the data in the array matches the data types and order of columns in the database table.

6. Summary

Bulk operations in Proc*C are a powerful feature that can significantly improve the efficiency and performance of data manipulation tasks. By leveraging array handling and the EXEC SQL FOR statement, you can process multiple rows of data in a single operation, reducing network overhead and execution time. Avoid common mistakes and refer to the FAQs for any queries related to bulk operations. With this understanding, you can optimize data manipulation and enhance the performance of your database-centric Proc*C applications.