Migrate Microsoft SQL Server T-SQL to Java

Conversion Samples of Microsoft SQL Server T‑SQL to Java

Ispirer Toolkit analyzes all object dependencies during the conversion process and provides not only line-by-line conversion, but resolves type conversions as well. The software understands and transforms the necessary inheritance dependencies. It parses the entire source code, builds an internal tree with all the information about the objects, and uses it in the migration process.

We convert SQL Server stored procedures to Java with attention to all the specifics

• System functions (GETDATE(), CONVERT, LEN). During migration, they are typically mapped to equivalent utility methods in our Java framework or standard libraries.
• Control flow (IF, WHILE, RETURN). In Java, these statements are directly translated to corresponding control structures (if, while, return), preserving the original logic flow.
• Error handling (TRY...CATCH, THROW, ERROR_MESSAGE(), ERROR_NUMBER() etc.). T-SQL error-handling mechanisms are represented by exception handling in Java. Errors are captured via try-catch blocks and delegated to utility classes (e.g., ErrorUtil) for unified exception processing and logging.
• Error logging into a dedicated table.
• Cursors for row-by-row processing.
• Output parameters to return additional values back to the caller. In Java, output parameters are typically represented as Map structures ensuring clarity in the returned results.

The code samples below provide you with more details.

• Microsoft SQL Server T-SQL

   
  CREATE PROCEDURE sp_demo_conversion
      @DeptId INT,
      @EmployeeCount INT OUTPUT   -- Output parameter
  AS
  BEGIN
   
      DECLARE @EmpId INT;
      DECLARE @EmpName NVARCHAR(100);
      DECLARE @CurrentDate DATETIME = GETDATE();
   
      PRINT 'Procedure started at ' + CONVERT(VARCHAR, @CurrentDate, 120);
   
      BEGIN TRY
          -- Validate input parameter
          IF @DeptId IS NULL OR @DeptId <= 0
              THROW 50001, 'Invalid Department Id', 1;
   
          -- Count employees in department and return via output parameter
          SELECT @EmployeeCount = COUNT(*) 
          FROM Employees
          WHERE DeptId = @DeptId;
   
          PRINT 'Total employees in department: ' + CAST(@EmployeeCount AS VARCHAR);
   
          -- Exit early if no employees found
          IF @EmployeeCount = 0
          BEGIN
              PRINT 'No employees found';
              RETURN;
          END
   
          -- Cursor to iterate employees
          DECLARE emp_cursor CURSOR FOR
              SELECT EmpId, EmpName 
              FROM Employees
              WHERE DeptId = @DeptId;
   
          OPEN emp_cursor;
   
          FETCH NEXT FROM emp_cursor INTO @EmpId, @EmpName;
   
          WHILE @@FETCH_STATUS = 0
          BEGIN
              -- Conditional branch
              IF LEN(@EmpName) > 10
                  PRINT 'Long name: ' + @EmpName;
              ELSE
                  PRINT 'Short name: ' + @EmpName;
   
              -- Try to update employee 
              UPDATE Employees
              SET LastUpdated = @CurrentDate
              WHERE EmpId = @EmpId;
   
              FETCH NEXT FROM emp_cursor INTO @EmpId, @EmpName;
          END
   
          CLOSE emp_cursor;
          DEALLOCATE emp_cursor;
      END TRY
   
      BEGIN CATCH
          -- Collect error details
          DECLARE @ErrMsg NVARCHAR(4000) = ERROR_MESSAGE();
          DECLARE @ErrNum INT = ERROR_NUMBER();
          DECLARE @ErrSeverity INT = ERROR_SEVERITY();
          DECLARE @ErrState INT = ERROR_STATE();
   
          PRINT 'Error occurred: ' + @ErrMsg;
   
          -- Log error into a dedicated table
          INSERT INTO ErrorLog (ErrorDate, ErrorNumber, Severity, State, Message)
          VALUES (GETDATE(), @ErrNum, @ErrSeverity, @ErrState, @ErrMsg);
   
          -- Re-throw the error for higher-level handling
          THROW;
      END CATCH;
   
      PRINT 'Procedure finished at ' + CONVERT(VARCHAR, GETDATE(), 120);
  END
   

  → Java

   
  import com.sql4j.db.cursor.*;
  import com.sql4j.db.implementation.Dao;
  import com.sql4j.db.util.ResultSetService;
  import com.sql4j.exception.*;
  import com.sql4j.transaction.aop.TransactionStatus;
  import com.sql4j.util.*;
  import java.time.LocalDateTime;
  import java.util.*;
  import org.springframework.beans.factory.annotation.Autowired;
  import org.springframework.stereotype.Service;
  import org.springframework.web.context.annotation.RequestScope;
  @Service
  @RequestScope
  public class SpDemoConversion implements ISpDemoConversion {
  	@Autowired
  	private ErrorUtil errorUtil;
  	@Autowired
  	private ResultSetService resultSetService;
  	@Autowired
  	private Dao dao;
  	@Autowired
  	private CursorStatusService cursorStatusService;
  	@TransactionStatus
  	@Override
  	public Map< String, Object > spSpDemoConversion(Integer deptid, Integer employeecount) {
  		Map<String, Object> outData = new HashMap<>();
  		outData.put("retStatus", 0);
   
  		try {
  			Integer empid = null;
  			String empname = null;
  			LocalDateTime currentdate = TimeUtil.getDate();
  			System.out.println(StringUtil.concatNullable("Procedure started at ", Converter.toString(currentdate, 120)));
   
  			try {
  				errorUtil.beginProtectedBlock();
   
  				if (deptid == null || ComparisonUtil.isLessOrEqual(deptid, 0)) {
  					errorUtil.throwError(50001, "Invalid Department Id", 1);
  				}
   
  				dao.selectRes("SELECT COUNT(*) " +
  				              "FROM Employees " +
  				              "WHERE DeptId = :DEPTID ", "DEPTID", deptid);
  				System.out.println(StringUtil.concatNullable("Total employees in department: ", Converter.toString(employeecount)));
   
  				if (ComparisonUtil.areEqual(employeecount, 0)) {
  					System.out.println("No employees found");
  					return outData;
  				}
   
  				CursorReader empCursor = new CursorReader(cursorStatusService, true, "SELECT EmpId, EmpName " +
  				        "FROM Employees " +
  				        "WHERE DeptId = :DEPTID ", "DEPTID", deptid);
  				empCursor.open();
   
  				if (empCursor.fetchNext()) {
  					empid = empCursor.getColumnValue(Integer.class);
  					empname = empCursor.getColumnValue(String.class);
  				}
   
  				while (ComparisonUtil.areEqual(cursorStatusService.getFetchStatus(), 0)) { // Conditional branch
  					if (ComparisonUtil.isGreaterThan(StringUtil.length(empname), 10)) {
  						System.out.println(StringUtil.concatNullable("Long name: ", empname));
  					}
  					else {
  						System.out.println(StringUtil.concatNullable("Short name: ", empname));
  					}
   
  					// Try to update employee
  					dao.update("UPDATE Employees " +
  					           "SET LastUpdated = :CURRENTDATE " +
  					           "WHERE EmpId = :EMPID ", "CURRENTDATE", currentdate, "EMPID", empid);
   
  					if (empCursor.fetchNext()) {
  						empid = empCursor.getColumnValue(Integer.class);
  						empname = empCursor.getColumnValue(String.class);
  					}
  				}
   
  				empCursor.close();
  				empCursor.deallocate();
  			}
  			catch (GeneralException e) {
  				errorUtil.failProtectedBlock();
  				String errmsg = e.getMessage();
  				Integer errnum = e.getErrorNumber();
  				Integer errseverity = e.getSeverity();
  				Integer errstate = e.getState();
  				System.out.println(StringUtil.concatNullable("Error occurred: ", errmsg));
  				dao.update("INSERT INTO ErrorLog (ErrorDate, ErrorNumber, Severity, State, Message) " +
  				           "VALUES (GETDATE(), :ERRNUM, :ERRSEVERITY, :ERRSTATE, :ERRMSG) ", "ERRNUM", errnum, "ERRSEVERITY", errseverity, "ERRSTATE", errstate, "ERRMSG", errmsg);
  				throw e;
  			}
  			finally {
  				errorUtil.finalizeProtectedBlock();
  			}
   
  			System.out.println(StringUtil.concatNullable("Procedure finished at ", Converter.toString(TimeUtil.getDate(), 120)));
  			return outData;
  		}
  		finally {
  			outData.put("dataSet", resultSetService.getResultSet());
  			outData.put("employeecount", employeecount);
  		}
  	}
  }