Package gudusoft.gsqlparser.resolver2.namespace

Class UnnestNamespace

Object

gudusoft.gsqlparser.resolver2.namespace.AbstractNamespace

gudusoft.gsqlparser.resolver2.namespace.UnnestNamespace

All Implemented Interfaces:

INamespace

public class UnnestNamespace
extends AbstractNamespace

Namespace representing an UNNEST table expression in BigQuery. UNNEST flattens an array into rows. For example: - UNNEST(['a', 'b', 'c']) creates a virtual table with rows 'a', 'b', 'c' - SELECT value FROM UNNEST(array_column) - 'value' is an implicit column name The UNNEST namespace provides: 1. An implicit column for the unnested elements (named by alias or 'value') 2. Support for WITH OFFSET which adds an 'offset' column 3. Support for STRUCT arrays which expose struct field names

Field Summary

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

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

Constructor Summary

Constructors

Constructor	Description
UnnestNamespace(TTable unnestTable, String alias)
UnnestNamespace(TTable unnestTable, 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<TTable>	getAllFinalTables()	Get all final physical tables this namespace depends on.
TExpression	getArrayExpression()	Get the array expression being unnested.
String	getDisplayName()	Get a display name for this namespace (for debugging/error messages)
TTable	getFinalTable()	Get the final physical table this namespace represents.
String	getImplicitColumnName()	Get the implicit column name for the unnested elements.
Set<String>	getInferredColumns()	Get all columns that were inferred (not from SELECT list directly).
String	getOffsetColumnName()	Get the offset column name if WITH OFFSET is present.
TTable	getSourceTable()	Get the TTable that this namespace is associated with.
TTable	getUnnestTable()
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.
ColumnSource	resolveQualifiedStructField(String columnName)	Resolve a qualified struct field reference (e.g., "alias.field").
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

getSelectStatement, getStarColumn, resolveColumnPath

Constructor Details

UnnestNamespace

public UnnestNamespace(TTable unnestTable,
 String alias,
 INameMatcher nameMatcher)

UnnestNamespace

public UnnestNamespace(TTable unnestTable,
 String alias)

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

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

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

resolveQualifiedStructField

public ColumnSource resolveQualifiedStructField(String columnName)

Resolve a qualified struct field reference (e.g., "alias.field"). This method infers struct fields when no metadata is available.

Use this method when resolving qualified column references like "x.field" where "x" is the UNNEST alias. This is appropriate for UNNEST of STRUCT arrays where the struct fields are accessed via the alias.

For unqualified column references, use resolveColumn(String) which does NOT infer columns and returns null for unknown columns.

Parameters:

columnName - the column/field name (without the table qualifier)

Returns:

ColumnSource for the inferred struct field

getArrayExpression

public TExpression getArrayExpression()

Get the array expression being unnested. This is used to track the source of the unnested data.

getImplicitColumnName

public String getImplicitColumnName()

Get the implicit column name for the unnested elements.

getOffsetColumnName

public String getOffsetColumnName()

Get the offset column name if WITH OFFSET is present.

getUnnestTable

public TTable getUnnestTable()

getSourceTable

public TTable getSourceTable()

Get the TTable that this namespace is associated with. Used for legacy sync to set TObjectName.sourceTable. For TableNamespace: returns the table itself For SubqueryNamespace: returns the TTable wrapping the subquery For CTENamespace: returns the CTE referencing table For others: returns null For UnnestNamespace, returns the TTable representing the UNNEST expression. This is the immediate source table for columns resolved through this UNNEST.

Returns:

The source TTable, or null if not applicable

toString

public String toString()

Overrides:

toString in class AbstractNamespace