SqlXmlAst is a toolkit to parse Oracle PlSql and generate Abstract Syntax Trees in XML.
As PlSql is a quite big language with many grammar rules, the resulting syntax trees are quite big even for the simplest queries.
To shorten the syntax trees a xslt3 stylesheet is used to post process raw syntax trees into a shorter form which is much more suitable for human consumption as well for further processing.
example SQL:
/* simple table alias - self join
from: https://www.oracletutorial.com/oracle-basics/oracle-alias/ */
SELECT e.first_name employee, m.first_name managerdir
FROM employees e
INNER
JOIN employees m
ON m.employee_id = e.employee_id;
The AST short form looks still a bit verbose, however from its form you can still tell which production rules in the grammar are applied.
<?xml version="1.0" encoding="UTF-8"?>
<ast xmlns="urn:xmlast:grammar"
xmlns:c="urn:xmlast:comment"
xmlns:t="urn:xmlast:token"
grammar="oracle"
path="plsql_alias_table1.sql"
numlines="6">
<q>/* simple table alias - self join
from: https://www.oracletutorial.com/oracle-basics/oracle-alias/ */</q>
<script>
<q>n</q>
<unit_statement path-ref="d725e6">
<b>SELECT</b>
<q>_</q>
<selected_list>
<select_list_elements>
<expression path-ref="d725e11">
<general_element path-ref="d725e12">
<regular_id>
<i val="e">e</i>
</regular_id>
</general_element>
<b>.</b>
<general_element_part path-ref="d725e17">
<regular_id>
<i val="first_name">first_name</i>
</regular_id>
</general_element_part>
</expression>
<q>_</q>
<column_alias path-ref="d725e22">
<regular_id>
<i val="employee">employee</i>
</regular_id>
</column_alias>
</select_list_elements>
<b>,</b>
<q>_</q>
<select_list_elements>
<expression path-ref="d725e11">
<general_element path-ref="d725e12">
<regular_id>
<i val="m">m</i>
</regular_id>
</general_element>
<b>.</b>
<general_element_part path-ref="d725e17">
<regular_id>
<i val="first_name">first_name</i>
</regular_id>
</general_element_part>
</expression>
<q>_</q>
<column_alias path-ref="d725e22">
<regular_id>
<i val="managerdir">managerdir</i>
</regular_id>
</column_alias>
</select_list_elements>
</selected_list>
<q>n</q>
<from_clause>
<b>FROM</b>
<q>___</q>
<table_ref_list>
<table_ref_aux>
<table_ref_aux_internal path-ref="d725e50">
<regular_id>
<i val="employees">employees</i>
</regular_id>
</table_ref_aux_internal>
<q>_</q>
<table_alias path-ref="d725e22">
<regular_id>
<i val="e">e</i>
</regular_id>
</table_alias>
</table_ref_aux>
<q>n</q>
<join_clause>
<b>INNER</b>
<q>n</q>
<b>JOIN</b>
<q>___</q>
<table_ref_aux>
<table_ref_aux_internal path-ref="d725e50">
<regular_id>
<i val="employees">employees</i>
</regular_id>
</table_ref_aux_internal>
<q>_</q>
<table_alias path-ref="d725e22">
<regular_id>
<i val="m">m</i>
</regular_id>
</table_alias>
</table_ref_aux>
<q>n</q>
<join_on_part>
<b>ON</b>
<q>_____</q>
<condition path-ref="d725e79">
<relational_expression path-ref="d725e80">
<general_element path-ref="d725e12">
<regular_id>
<i val="m">m</i>
</regular_id>
</general_element>
<b>.</b>
<general_element_part path-ref="d725e17">
<regular_id>
<i val="employee_id">employee_id</i>
</regular_id>
</general_element_part>
</relational_expression>
<q>_</q>
<relational_operator>
<b>=</b>
</relational_operator>
<q>_</q>
<relational_expression path-ref="d725e80">
<general_element path-ref="d725e12">
<regular_id>
<i val="e">e</i>
</regular_id>
</general_element>
<b>.</b>
<general_element_part path-ref="d725e17">
<regular_id>
<i val="employee_id">employee_id</i>
</regular_id>
</general_element_part>
</relational_expression>
</condition>
</join_on_part>
</join_clause>
</table_ref_list>
</from_clause>
</unit_statement>
<b>;</b>
</script>
<path-map>
<entry path="compound_expression/concatenation/model_expression/unary_expression/atom"
path-def="d725e80"/>
<entry path="data_manipulation_language_statements/select_statement/select_only_statement/subquery/subquery_basic_elements"
path-def="d725e6"/>
<entry path="dml_table_expression_clause/tableview_name/dot_expression/identifier/id_expression"
path-def="d725e50"/>
<entry path="expression/logical_expression/unary_logical_expression/multiset_expression"
path-def="d725e79"/>
<entry path="general_element_part/id_expression" path-def="d725e12"/>
<entry path="id_expression" path-def="d725e17"/>
<entry path="identifier/id_expression" path-def="d725e22"/>
<entry path="logical_expression/unary_logical_expression/multiset_expression/relational_expression/compound_expression/concatenation/model_expression/unary_expression/atom"
path-def="d725e11"/>
</path-map>
</ast>
Notes:
- path-refs are used to compress nested rule elements which only contain one child.
- html elements are used for terminals ** b for sql language tokens ** i for id expressions ** q for whitespace (_ is space, t is tab, n is new line, r is cariage return)
<project name="test.sqlxmlast">
<taskdef name="sqlxmlast" classname="nl.xs4all.home.ei.parsers.antlr.SqlXmlAstAntTask"
classpath="${test_classpath}"/>
<target name="testOracle">
<sqlxmlast grammar="oracle"
basedir="examples/plsql"
destdir="target/sqlxmlast/plsql">
<filename name="**/*.sql"/>
</sqlxmlast>
</target>
</project>