Package gudusoft.gsqlparser.resolver2.namespace

Class UnionNamespace

Object

gudusoft.gsqlparser.resolver2.namespace.AbstractNamespace

gudusoft.gsqlparser.resolver2.namespace.UnionNamespace

All Implemented Interfaces:

INamespace

public class UnionNamespace
extends AbstractNamespace

Namespace representing a UNION/INTERSECT/EXCEPT query. Key characteristics: - Schema is defined by the FIRST branch (SQL standard) - Columns must be pushed down to ALL branches - hasStarColumn() returns true if ANY branch has SELECT * - addInferredColumn() propagates to ALL branches Example: FROM ( SELECT * FROM table_1 UNION ALL SELECT * FROM table_2 UNION ALL SELECT * FROM table_3 ) Combined When outer query references "col_1", it should be pushed to ALL branches.

Field Summary

Fields inherited from class gudusoft.gsqlparser.resolver2.namespace.AbstractNamespace

columnSources, columnSourcesWithRefs, guessColumnStrategy, nameMatcher, node, referenceTraceabilityEnabled, validated

Constructor Summary

Constructors

Constructor	Description
UnionNamespace(TSelectSqlStatement unionQuery, String alias, INameMatcher nameMatcher)

Method Summary

Modifier and Type	Method	Description
boolean	addInferredColumn(String columnName, double confidence, String evidence)	Add an inferred column to this namespace.
protected void	doValidate()	Subclasses override this to perform actual validation logic.
List<TSelectSqlStatement>	getAllBranches()	Get all branch SELECT statements.
List<TTable>	getAllFinalTables()	Get all final physical tables this namespace depends on.
int	getBranchCount()	Get the number of UNION branches.
List<SubqueryNamespace>	getBranchNamespaces()	Get all branch namespaces.
String	getDisplayName()	Get a display name for this namespace (for debugging/error messages)
TTable	getFinalTable()	Get the final physical table this namespace represents.
Set<String>	getInferredColumns()	Get all columns that were inferred (not from SELECT list directly).
TSelectSqlStatement	getSelectStatement()	Get the underlying SELECT statement for this namespace.
ColumnLevel	hasColumn(String columnName)	Check if a column exists in this namespace.
boolean	hasStarColumn()	Check if this namespace contains a star column (SELECT *).
ColumnSource	resolveColumn(String columnName)	Resolve a column name to its source.
boolean	supportsDynamicInference()	Check if this namespace supports dynamic column inference.
String	toString()

Methods inherited from class gudusoft.gsqlparser.resolver2.namespace.AbstractNamespace

addColumnSource, addColumnSource, enableReferenceTraceability, ensureValidated, getAllColumnSources, getAllUniqueColumns, getColumnReferences, getColumnSourceWithReferences, getGuessColumnStrategy, getNameMatcher, getNode, isReferenceTraceabilityEnabled, isValidated, setGuessColumnStrategy, validate

Methods inherited from class java.lang.Object

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

Methods inherited from interface gudusoft.gsqlparser.resolver2.namespace.INamespace

getSourceTable, getStarColumn, resolveColumnPath

Constructor Details

UnionNamespace

public UnionNamespace(TSelectSqlStatement unionQuery,
 String alias,
 INameMatcher nameMatcher)

Method Details

getDisplayName

public String getDisplayName()

Description copied from interface: INamespace

Get a display name for this namespace (for debugging/error messages)

getFinalTable

public TTable getFinalTable()

Description copied from interface: INamespace

Get the final physical table this namespace represents. For tables: returns the table itself For subqueries/CTEs: recursively traces back to physical table(s)

Returns:

Physical table, or null if not determinable

getAllFinalTables

public List<TTable> getAllFinalTables()

Description copied from interface: INamespace

Get all final physical tables this namespace depends on. For simple table namespace: returns single table For subquery/CTE: returns all tables in the query tree

Specified by:

getAllFinalTables in interface INamespace

Overrides:

getAllFinalTables in class AbstractNamespace

Returns:

List of all physical tables

doValidate

protected void doValidate()

Description copied from class: AbstractNamespace

Subclasses override this to perform actual validation logic.

Specified by:

doValidate in class AbstractNamespace

hasColumn

public ColumnLevel hasColumn(String columnName)

Description copied from interface: INamespace

Check if a column exists in this namespace. Returns a three-level answer: EXISTS, MAYBE, NOT_EXISTS

Specified by:

hasColumn in interface INamespace

Overrides:

hasColumn in class AbstractNamespace

Parameters:

columnName - Column name to check

Returns:

Column existence level

resolveColumn

public ColumnSource resolveColumn(String columnName)

Description copied from interface: INamespace

Resolve a column name to its source.

Specified by:

resolveColumn in interface INamespace

Overrides:

resolveColumn in class AbstractNamespace

Parameters:

columnName - Column name to resolve

Returns:

ColumnSource if found, null otherwise

getSelectStatement

public TSelectSqlStatement getSelectStatement()

Description copied from interface: INamespace

Get the underlying SELECT statement for this namespace. For CTENamespace: returns the CTE's subquery For SubqueryNamespace: returns the subquery For TableNamespace: returns null

Returns:

the SELECT statement, or null if not applicable

hasStarColumn

public boolean hasStarColumn()

Description copied from interface: INamespace

Check if this namespace contains a star column (SELECT *). Used to identify namespaces that may need star column inference.

Returns:

true if the namespace has SELECT *, false otherwise

supportsDynamicInference

public boolean supportsDynamicInference()

Description copied from interface: INamespace

Check if this namespace supports dynamic column inference. DynamicStarSource and similar namespaces return true.

Returns:

true if this namespace can have columns added dynamically

addInferredColumn

public boolean addInferredColumn(String columnName,
 double confidence,
 String evidence)

Description copied from interface: INamespace

Add an inferred column to this namespace. Used by star column push-down to add columns discovered from outer queries.

Parameters:

columnName - the column name to add

confidence - the confidence score (0.0 to 1.0)

evidence - description of why this column was inferred

Returns:

true if the column was added, false if already exists

getInferredColumns

public Set<String> getInferredColumns()

Description copied from interface: INamespace

Get all columns that were inferred (not from SELECT list directly). These are columns discovered through star column push-down.

Returns:

set of inferred column names, empty if none

getBranchNamespaces

public List<SubqueryNamespace> getBranchNamespaces()

Get all branch namespaces. Useful for external code that needs to iterate over branches.

getAllBranches

public List<TSelectSqlStatement> getAllBranches()

Get all branch SELECT statements.

getBranchCount

public int getBranchCount()

Get the number of UNION branches.

toString

public String toString()

Overrides:

toString in class AbstractNamespace