Package gudusoft.gsqlparser.resolver2.inference

Class EvidenceCollector

Object

gudusoft.gsqlparser.resolver2.inference.EvidenceCollector

public class EvidenceCollector
extends Object

Collects evidence for column inference from SQL statements.

The collector traverses various parts of SQL statements to gather evidence about which columns belong to which tables. This is used by the InferenceEngine to make educated guesses about column sources when metadata is not available.

Evidence sources: - WHERE clause: qualified and unqualified column references - JOIN conditions: columns used in join predicates - SELECT list: columns and expressions - GROUP BY: grouped columns - ORDER BY: sort columns - INSERT statements: column lists - UPDATE statements: SET clauses

Example:

 SELECT * FROM employees e
 WHERE e.department_id = 10

 Evidence collected:
 - "department_id" in "employees" (from qualified WHERE reference)
 

Constructor Summary

Constructors

Constructor	Description
EvidenceCollector()

Method Summary

Modifier and Type	Method	Description
void	clear()	Clear all collected evidence.
List<InferenceEvidence>	collectFromSelect(TSelectSqlStatement select)	Collect evidence from a SELECT statement.
List<InferenceEvidence>	getEvidence()	Get all collected evidence.
int	getEvidenceCount()	Get count of collected evidence.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

EvidenceCollector

public EvidenceCollector()

Method Details

collectFromSelect

public List<InferenceEvidence> collectFromSelect(TSelectSqlStatement select)

Collect evidence from a SELECT statement.

Parameters:

select - the SELECT statement

Returns:

list of collected evidence

getEvidence

public List<InferenceEvidence> getEvidence()

Get all collected evidence.

Returns:

list of evidence

clear

public void clear()

Clear all collected evidence.

getEvidenceCount

public int getEvidenceCount()

Get count of collected evidence.

Returns:

evidence count