gudusoft.gsqlparser.resolver2.inference

Class InferenceEngine

Object

gudusoft.gsqlparser.resolver2.inference.InferenceEngine

public class InferenceEngine
extends Object

Engine for inferring column-to-table relationships without metadata.

The inference engine collects evidence from various sources in the SQL statement and uses it to infer which columns belong to which tables. This is particularly useful when: - Database metadata is not available - Dealing with SELECT * without schema information - Analyzing SQL from unknown sources

Inference process: 1. Collect evidence from SQL statement (WHERE, JOIN, SELECT, etc.) 2. Aggregate evidence by table and column 3. Calculate confidence scores 4. Generate inferred column sources

Example:

 SELECT * FROM employees e
 WHERE e.department_id = 10
   AND e.salary > 50000

 Inference:
 - "department_id" column exists in "employees" (confidence: 0.95)
 - "salary" column exists in "employees" (confidence: 0.95)
 

Constructor Summary

Constructors

Constructor and Description
InferenceEngine()

Method Summary

Modifier and Type	Method and Description
void	addAllEvidence(Collection<InferenceEvidence> evidences) Add multiple pieces of evidence.
void	addEvidence(InferenceEvidence evidence) Add a piece of evidence for inference.
double	calculateConfidence(String tableName, String columnName) Calculate the combined confidence for a table.column based on all evidence.
void	clear() Clear all evidence and inferred columns.
ColumnSource	createInferredColumnSource(String tableName, String columnName, TTable table) Create an inferred ColumnSource for a table.column.
List<InferenceEvidence>	getEvidence(String tableName, String columnName) Get all evidence for a specific table.column.
int	getEvidenceCount() Get total number of pieces of evidence collected.
int	getInferredColumnCount() Get total number of inferred columns across all tables.
Set<String>	getInferredColumns(String tableName) Get all inferred columns for a table.
String	getStatistics() Get statistics about the inference engine state.
Set<String>	getTablesWithInferences() Get all tables that have inferred columns.
String	toString()

Methods inherited from class Object

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

Constructor Detail

InferenceEngine

public InferenceEngine()

Method Detail

addEvidence

public void addEvidence(InferenceEvidence evidence)

Add a piece of evidence for inference.

Parameters:

evidence - the evidence to add

addAllEvidence

public void addAllEvidence(Collection<InferenceEvidence> evidences)

Add multiple pieces of evidence.

Parameters:

evidences - the evidence to add

getInferredColumns

public Set<String> getInferredColumns(String tableName)

Get all inferred columns for a table.

Parameters:

tableName - the table name

Returns:

set of inferred column names, or empty set if none

getEvidence

public List<InferenceEvidence> getEvidence(String tableName,
                                           String columnName)

Get all evidence for a specific table.column.

Parameters:

tableName - the table name

columnName - the column name

Returns:

list of evidence, or empty list if none

calculateConfidence

public double calculateConfidence(String tableName,
                                  String columnName)

Calculate the combined confidence for a table.column based on all evidence.

Combines multiple pieces of evidence using formula:

 combined = 1 - ∏(1 - conf_i)
 

This means: - Multiple pieces of evidence increase confidence - Evidence is independent (multiplicative combination) - Result is always in [0, 1]

Parameters:

tableName - the table name

columnName - the column name

Returns:

combined confidence [0.0, 1.0], or 0.0 if no evidence

createInferredColumnSource

public ColumnSource createInferredColumnSource(String tableName,
                                               String columnName,
                                               TTable table)

Create an inferred ColumnSource for a table.column.

Parameters:

tableName - the table name

columnName - the column name

table - the TTable object (may be null if not available)

Returns:

ColumnSource with inferred confidence, or null if no evidence

getTablesWithInferences

public Set<String> getTablesWithInferences()

Get all tables that have inferred columns.

Returns:

set of table names with inferred columns

getEvidenceCount

public int getEvidenceCount()

Get total number of pieces of evidence collected.

Returns:

evidence count

getInferredColumnCount

public int getInferredColumnCount()

Get total number of inferred columns across all tables.

Returns:

inferred column count

clear

public void clear()

Clear all evidence and inferred columns.

getStatistics

public String getStatistics()

Get statistics about the inference engine state.

Returns:

summary string

toString

public String toString()

Overrides:

toString in class Object