Support parsing Oracle CREATE OR sql

[FlyingZC]

Background

Hi community, This issue is for #26878.

ShardingSphere parser engine helps users parse a SQL to get the AST (Abstract Syntax Tree) and visit this tree to get SQLStatement (Java Object). Currently, we are planning to enhance the support for Oracle SQL parsing in ShardingSphere.

More details: https://shardingsphere.apache.org/document/current/en/reference/sharding/parse/

Task

This issue is to support more oracle sql parse, as follows:

CREATE OR REPLACE TRIGGER my_trigger
  AFTER CREATE ON DATABASE
BEGIN
  NULL;
END;

CREATE OR REPLACE PACKAGE My_Types AUTHID DEFINER IS
  TYPE My_AA IS TABLE OF VARCHAR2(20) INDEX BY PLS_INTEGER;
  FUNCTION Init_My_AA RETURN My_AA;
END My_Types;

CREATE OR REPLACE TRIGGER emp_dept_check
  BEFORE INSERT OR UPDATE OF Deptno ON emp
  FOR EACH ROW WHEN (NEW.Deptno IS NOT NULL)

  -- Before row is inserted or DEPTNO is updated in emp table,
  -- fire this trigger to verify that new foreign key value (DEPTNO)
  -- is present in dept table.
DECLARE
  Dummy               INTEGER;  -- Use for cursor fetch
  Invalid_department  EXCEPTION;
  Valid_department    EXCEPTION;
  Mutating_table      EXCEPTION;
  PRAGMA EXCEPTION_INIT (Mutating_table, -4091);

  -- Cursor used to verify parent key value exists.
  -- If present, lock parent key's row so it cannot be deleted
  -- by another transaction until this transaction is
  -- committed or rolled back.

  CURSOR Dummy_cursor (Dn NUMBER) IS
    SELECT Deptno FROM dept
    WHERE Deptno = Dn
    FOR UPDATE OF Deptno;
BEGIN
  OPEN Dummy_cursor (:NEW.Deptno);
  FETCH Dummy_cursor INTO Dummy;

  -- Verify parent key.
  -- If not found, raise user-specified error code and message.
  -- If found, close cursor before allowing triggering statement to complete:

  IF Dummy_cursor%NOTFOUND THEN
    RAISE Invalid_department;
  ELSE
    RAISE valid_department;
  END IF;
  CLOSE Dummy_cursor;
EXCEPTION
  WHEN Invalid_department THEN
    CLOSE Dummy_cursor;
    Raise_application_error(-20000, 'Invalid Department'
      || ' Number' || TO_CHAR(:NEW.deptno));
  WHEN Valid_department THEN
    CLOSE Dummy_cursor;
  WHEN Mutating_table THEN
    NULL;
END;

CREATE OR REPLACE TRIGGER print_salary_changes
  BEFORE DELETE OR INSERT OR UPDATE ON employees
  FOR EACH ROW
  WHEN (NEW.job_id <> 'AD_PRES')  -- do not print information about President
DECLARE
  sal_diff  NUMBER;
BEGIN
  sal_diff  := :NEW.salary  - :OLD.salary;
  DBMS_OUTPUT.PUT(:NEW.last_name || ': ');
  DBMS_OUTPUT.PUT('Old salary = ' || :OLD.salary || ', ');
  DBMS_OUTPUT.PUT('New salary = ' || :NEW.salary || ', ');
  DBMS_OUTPUT.PUT_LINE('Difference: ' || sal_diff);
END;

CREATE OR REPLACE TRIGGER salary_check
  BEFORE INSERT OR UPDATE OF Sal, Job ON Emp
  FOR EACH ROW
DECLARE
  Minsal               NUMBER;
  Maxsal               NUMBER;
  Salary_out_of_range  EXCEPTION;

BEGIN
  /* Retrieve minimum & maximum salary for employee's new job classification
     from SALGRADE table into MINSAL and MAXSAL: */

  SELECT Minsal, Maxsal INTO Minsal, Maxsal
  FROM Salgrade
  WHERE Job_classification = :NEW.Job;

  /* If employee's new salary is less than or greater than
     job classification's limits, raise exception.
     Exception message is returned and pending INSERT or UPDATE statement
     that fired the trigger is rolled back: */

  IF (:NEW.Sal < Minsal OR :NEW.Sal > Maxsal) THEN
    RAISE Salary_out_of_range;
  END IF;
EXCEPTION
  WHEN Salary_out_of_range THEN
    Raise_application_error (
      -20300,
      'Salary '|| TO_CHAR(:NEW.Sal) ||' out of range for '
      || 'job classification ' ||:NEW.Job
      ||' for employee ' || :NEW.Ename
    );
  WHEN NO_DATA_FOUND THEN
    Raise_application_error(-20322, 'Invalid Job Classification');
END;

Process

1. First confirm that this is a correct oracle sql syntax, if not please ignore;
2. Compare SQL definitions in Oficial SQL Doc and ShardingSphere SQL Doc;
3. If there is any difference in ShardingSphere SQL Doc, please correct them by referring to the Official SQL Doc;
4. Run mvn install the current_file_module;
5. Check whether there are any exceptions. If indeed, please fix them. (Especially xxxVisitor.class);
6. Add new corresponding SQL case in SQL Cases and expected parsed result in Expected Statment XML;
7. Run SQLParserParameterizedTest to make sure no exceptions.

Relevant Skills

1. Master JAVA language
2. Have a basic understanding of Antlr g4 file
3. Be familiar with Oracle SQLs

[github-actions[bot]]

There hasn't been any activity on this issue recently, and in order to prioritize active issues, it will be marked as stale.

[github-actions[bot]]

There hasn't been any activity on this issue recently, and in order to prioritize active issues, it will be marked as stale.