FlyingZC opened a new issue, #27070:
URL: https://github.com/apache/shardingsphere/issues/27070

   # 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:
   ```sql
   CREATE OR REPLACE TRIGGER dept_set_null
     AFTER DELETE OR UPDATE OF Deptno ON dept
     FOR EACH ROW
   
     -- Before row is deleted from dept or primary key (DEPTNO) of dept is 
updated,
     -- set all corresponding dependent foreign key values in emp to NULL:
   
   BEGIN
     IF UPDATING AND :OLD.Deptno != :NEW.Deptno OR DELETING THEN
       UPDATE emp SET emp.Deptno = NULL
       WHERE emp.Deptno = :OLD.Deptno;
     END IF;
   END;
   ```
   
   ```sql
   CREATE OR REPLACE TRIGGER drop_trigger
     BEFORE DROP ON hr.SCHEMA
     BEGIN
       RAISE_APPLICATION_ERROR (
         num => -20000,
         msg => 'Cannot drop object');
     END;
   ```
   
   ```sql
   CREATE OR REPLACE TRIGGER employees_tr
     AFTER INSERT ON employees
     FOR EACH ROW
   BEGIN
     -- When remote database is unavailable, compilation fails here:
     INSERT INTO employees@remote (
       employee_id, first_name, last_name, email, hire_date, job_id
     ) 
     VALUES (
       99, 'Jane', 'Doe', '[email protected]', SYSDATE, 'ST_MAN'
     );
   EXCEPTION
     WHEN OTHERS THEN
       INSERT INTO emp_log (Emp_id, Log_date, New_salary, Action)
         VALUES (99, SYSDATE, NULL, 'Could not insert');
       RAISE;
   END;
   ```
   
   ```sql
   CREATE OR REPLACE TRIGGER employees_tr
     AFTER INSERT ON employees
     FOR EACH ROW
   BEGIN
     insert_row_proc;
   END;
   ```
   
   ```sql
   CREATE OR REPLACE TRIGGER log_salary_increase
     AFTER UPDATE OF salary ON employees
     FOR EACH ROW
   BEGIN
     INSERT INTO Emp_log (Emp_id, Log_date, New_salary, Action)
     VALUES (:NEW.employee_id, SYSDATE, :NEW.salary, 'New Salary');
   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


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