dt-sql-parser-semantic-analyse-plugin

A dt-sql-parser plugin with semantic result. Theory(zh-CN).

Installation

npm install dt-sql-parser-semantic-analyse-plugin

Quick Usage

import { PostgreSQL } from 'dt-sql-parser'
import { PostgreSqlParser } from 'dt-sql-parser/dist/lib/postgresql/PostgreSqlParser'

const myPlugin = new DtSqlParserSemAnalysePlugin({
  parse: {
    sql: new PostgreSQL(),
    parser: PostgreSqlParser,
    alias: {
      selectstmt: 'selectStatement',
    },
    stmts: [
      'selectstmt',
    ],
    entities: [
      'target_el',
    ],
    rules: {
      select_target: [
        PostgreSqlParser.RULE_selectstmt,
        PostgreSqlParser.RULE_target_el,
      ]
    }
  }
})

const sql = 'SELECT a| FROM t'
const caretColumn = sql.indexOf('|') + 1
const result = myPlugin.parse(sql.replace('|', ''), { lineNumber: 1, columnNumber: caretColumn })
console.log(result)

This will use a postgresql Parser. You can get select_target text from parse result.

Notice: A rule must start with a/an statement/entity and stop with an entity. You should add a node keywords(keyword is in your parser with format: RULE_[keyword]) into stmts/entities before using it.

Add a preprocessor

const myPlugin = new DtSqlParserSemAnalysePlugin({
  preprocessor: [
    (sql) => sql.toUpperCase(),
    ...
  ],
  parse: {
    ...
  }
})

Rule Chain Operator

You can set a negative number whose abs equals to a ruleIndex. That means exclude this rule.

Example:

select_target_alias: [
  PostgreSqlParser.RULE_target_el,
  -PostgreSqlParser.RULE_attr_name,
  PostgreSqlParser.RULE_collabel
]

🚧 I will later work on Operator.AND and Operator.OR.

Alias

Some node names in dt-sql-parser's code are different from their antlr4's definition. You should declare them in alias params.

Example:

const myPlugin = new DtSqlParserSemAnalysePlugin({
  parse: {
    ...
    alias: {
      selectstmt: 'selectStatement',
      target_el: 'target_label',
      table_name: 'tableName',
      ...
    }
    ...
  }
})

You can find possible alias in https://github.com/DTStack/dt-sql-parser/blob/main/src/grammar/postgresql/PostgreSqlParser.g4, then add it into alias option.

Custom dt-sql-parser

If you want to use your custom dt-sql-parser, with external grammar(such as DISTRIBUTED, etc.), follow steps below:

1. fork dt-sql-parser.
2. change its ANTLR4 file as whatever you want.
3. build asn publish your dt-sql-parser npm package(npm run antlr4 && npm publish). Suppose to be my-dt-sql-parser.
4. use my-dt-sql-parser instead of dt-sql-parser to provide parse.sql and parse.parser.

Example:

import { PostgreSQL } from 'my-dt-sql-parser'
import { PostgreSqlParser } from 'my-dt-sql-parser/dist/lib/postgresql/PostgreSqlParser'
const myPlugin = new DtSqlParserSemAnalysePlugin({
  parse: {
    sql: new PostgreSQL(),
    parser: PostgreSqlParser,
    ...
  }
})