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 TABLE dept_external (
   deptno     NUMBER(6),
   dname      VARCHAR2(20),
   loc        VARCHAR2(25) 
)
ORGANIZATION EXTERNAL
(TYPE oracle_loader
 DEFAULT DIRECTORY admin
 ACCESS PARAMETERS
 (
  RECORDS DELIMITED BY newline
  BADFILE 'ulcase1.bad'
  DISCARDFILE 'ulcase1.dis'
  LOGFILE 'ulcase1.log'
  SKIP 20
  FIELDS TERMINATED BY ","  OPTIONALLY ENCLOSED BY '"'
  (
   deptno     INTEGER EXTERNAL(6),
   dname      CHAR(20),
   loc        CHAR(25)
  )
 )
 LOCATION ('ulcase1.ctl')
)
REJECT LIMIT UNLIMITED;

CREATE TABLE dept_xt (dept_no INT, dept_name CHAR(20), location CHAR(20))
ORGANIZATION EXTERNAL (TYPE ORACLE_DATAPUMP DEFAULT DIRECTORY load_dir 
ACCESS PARAMETERS (LOGFILE log_dir:deptxt) LOCATION ('dept_dmp'));

CREATE TABLE emp (
    empno NUMBER(5) CONSTRAINT emp.pk PRIMARY KEY,   . . . ;

ALTER TABLE emp
    ADD CONSTRAINT emp.pk PRIMARY KEY (empno);

CREATE TABLE dept_20 
   (employee_id     NUMBER(4), 
    last_name       VARCHAR2(10), 
    job_id          VARCHAR2(9), 
    manager_id      NUMBER(4), 
    hire_date       DATE, 
    salary          NUMBER(7,2), 
    commission_pct  NUMBER(7,2), 
    department_id, 
   CONSTRAINT fk_deptno 
      FOREIGN  KEY (department_id) 
      REFERENCES  departments(department_id) );

CREATE TABLE emp_ext (
     first_name,
     last_name,
     empID,
     salary,
     ssn ENCRYPT IDENTIFIED BY "xIcf3T9u"
)  ORGANIZATION EXTERNAL
   (
    TYPE ORACLE_DATAPUMP
    DEFAULT DIRECTORY "D_DIR"
    LOCATION('emp_ext.dat')
    )
    REJECT LIMIT UNLIMITED
AS SELECT * FROM EMPLOYEE;

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