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 t
  INSTEAD OF CREATE ON SCHEMA
  BEGIN
    EXECUTE IMMEDIATE 'CREATE TABLE T (n NUMBER, m NUMBER)';
  END;

CREATE OR REPLACE TRIGGER trigger1
  BEFORE INSERT OR UPDATE ON table1
  FOR EACH ROW
  CROSSEDITION
DECLARE
  row_already_present  EXCEPTION;
  PRAGMA EXCEPTION_INIT(row_already_present, -38911);
BEGIN
  IF APPLYING_CROSSEDITION_TRIGGER THEN
    /* Trigger is running because of serendipitous change.
       Insert new row into table2 unless it is already there. */
    INSERT /*+ IGNORE_ROW_ON_DUPKEY_INDEX(table2(key)) */
    INTO table2
    VALUES(:new.key, :new.value, to_date('1900-01-01', 'YYYY-MM-DD'));
  ELSE
    /* Trigger is running because you are applying transform.
       If tranform has not yet inserted new row in table2, insert new row;
       otherwise, update new row. */
    BEGIN
      INSERT /*+ CHANGE_DUPKEY_ERROR_INDEX(table2(key)) */
      INTO table2
      VALUES(:new.key, :new.value, SYSTIMESTAMP);
    EXCEPTION WHEN row_already_present THEN
      UPDATE table2
      SET value = :new.value, last_updated = SYSTIMESTAMP
      WHERE key = :new.key;
    END;
  END IF;
END;

CREATE OR REPLACE VIEW dept_xml OF XMLType
  XMLSCHEMA "http://www.oracle.com/dept_complex.xsd" ELEMENT "Department"
  WITH OBJECT ID (XMLCast(XMLQuery('/Department/DEPTNO'
                                   PASSING OBJECT_VALUE RETURNING CONTENT)
                          AS BINARY_DOUBLE)) AS
  SELECT  
    XMLElement(
      "Department",
      XMLAttributes('http://www.oracle.com/dept_complex.xsd' AS "xmlns",        
                    'http://www.w3.org/2001/XMLSchema-instance' AS "xmlns:xsi",
                    'http://www.oracle.com/dept_complex.xsd 
                     http://www.oracle.com/dept_complex.xsd' 
                      AS "xsi:schemaLocation"),
      XMLForest(d.department_id "DeptNo", d.department_name "DeptName",
                d.location_id "Location"),
      (SELECT XMLAgg(XMLElement("Employee",
                                XMLForest(e.employee_id "EmployeeId", 
                                          e.last_name "Name", 
                                          e.job_id "Job", 
                                          e.manager_id "Manager", 
                                          e.hire_date "Hiredate",
                                          e.salary "Salary",
                                          e.commission_pct "Commission")))
                      FROM employees e WHERE e.department_id = d.department_id))
    FROM departments d;

CREATE OR REPLACE VIEW emp_view AS 
  SELECT last_name, department_name FROM employees e, departments d
  WHERE e.department_id=d.department_id;

CREATE OR REPLACE VIEW emp_xml OF XMLType
     XMLSCHEMA "emp-noname.xsd" ELEMENT "Employee"
     WITH OBJECT ID (XMLCast(XMLQuery('/Employee/EmployeeId/text()'
                                      PASSING OBJECT_VALUE
                                      RETURNING CONTENT)
                             AS BINARY_DOUBLE)) AS
     SELECT XMLElement(
       "Employee",
       XMLAttributes('http://www.w3.org/2001/XMLSchema-instance' AS "xmlns:xsi",
                     'emp-noname.xsd' AS "xsi:noNamespaceSchemaLocation"),
       XMLForest(e.employee_id    AS "EmployeeId",
                 e.last_name      AS "Name",
                 e.job_id         AS "Job",
                 e.manager_id     AS "Manager",
                 e.hire_date      AS "HireDate",
                 e.salary         AS "Salary",
                 e.commission_pct AS "Commission",
                 XMLForest(d.department_id   AS "DeptNo",
                           d.department_name AS "DeptName",
                           d.location_id     AS "Location") AS "Dept"))
       FROM employees e, departments d
       WHERE e.department_id = d.department_id;

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.