[GSOC-213] Apache ShardingSphere: Proofread the DML SQL definitions for ShardingSphere Parser

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Labels: Mentor ShardingSphere gsoc2021
• Assignee: Unassigned
• Reporter: Juan Pan
• Created: 16/Nov/20 06:52
• Updated: 21/Mar/23 08:11

Description

Apache ShardingSphere

Apache ShardingSphere is a distributed database middleware ecosystem, including 2 independent products, ShardingSphere JDBC and ShardingSphere Proxy presently. They all provide functions of data sharding, distributed transaction, and database orchestration.
Page: https://shardingsphere.apache.org
Github: https://github.com/apache/shardingsphere

Background

ShardingSphere parser engine helps users parse a SQL to get the AST (Abstract Syntax Tree) and visit this tree to get SQLStatement (Java Object). At present, this parser engine can handle SQLs for `MySQL`, `PostgreSQL`, `SQLServer` and `Oracle`, which means we have to understand different database dialect SQLs.
More details: https://shardingsphere.apache.org/document/current/en/features/sharding/principle/parse/

Task

This issue is to proofread the DML(SELECT/UPDATE/DELETE/INSERT) SQL definitions for Oracle. As we have a basic Oracle SQL syntax definitions but do not keep in line with Oracle DOC, we need you to find out the vague SQL grammar definitions and correct them referring to Oracle DOC.

Notice, when you review these DML(SELECT/UPDATE/DELETE/INSERT) SQLs, you will find that these definitions will involve some basic elements of Oracle SQL. No doubt, these elements are included in this task as well.

Relevant Skills

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

Targets files

1. DML SQLs g4 file: https://github.com/apache/shardingsphere/blob/master/shardingsphere-sql-parser/shardingsphere-sql-parser-dialect/shardingsphere-sql-parser-oracle/src/main/antlr4/imports/oracle/DMLStatement.g4
2. Basic elements g4 file: https://github.com/apache/shardingsphere/blob/master/shardingsphere-sql-parser/shardingsphere-sql-parser-dialect/shardingsphere-sql-parser-oracle/src/main/antlr4/imports/oracle/BaseRule.g4

References

1. Oracle SQL quick reference: https://docs.oracle.com/en/database/oracle/oracle-database/19/sqlqr/SQL-Statements.html#GUID-1FA35EAD-AED2-4619-BFEE-348FF05D1F4A
2. Detailed Oracle SQL info: https://docs.oracle.com/pls/topic/lookup?ctx=en/database/oracle/oracle-database/19/sqlqr&id=SQLRF008

Mentor

Juan Pan, PMC of Apache ShardingSphere, [e-mail]