gudusoft.gsqlparser.resolver2.scope

Class SelectScope.UsingMerge

Object

gudusoft.gsqlparser.resolver2.scope.SelectScope.UsingMerge

Enclosing class:

SelectScope

public static final class SelectScope.UsingMerge
extends Object

One JOIN ... USING merge in this scope: the names it merged, the relations that took part, in JOIN ORDER, and the join type.

SQL exposes a merged column ONCE, so an unqualified reference to it is not ambiguous across the sides that merged it. All three fields are needed to say that safely:

• the NAMES, because only those columns merge;
• the PARTICIPANTS, because a third relation in the same scope carrying the same name is still a genuine ambiguity — SELECT c FROM a JOIN b USING(c), d has three candidates and only two of them merged;
• the ORDER and the join TYPE, because which side the merged value comes from depends on them: the left for INNER and LEFT, the right for RIGHT, and both for FULL.

Constructor Summary

Constructors

Constructor and Description
UsingMerge(EJoinType joinType)

Method Summary

Modifier and Type	Method and Description
void	addColumnName(String name)
void	addParticipant(TTable table) Participants are added LEFT side first, right side last, and the order is meaningful.
EJoinType	getJoinType()
List<TTable>	getParticipants()
boolean	hasParticipant(TTable table)
boolean	merges(EDbVendor vendor, String columnName) Identifiers fold by the vendor's rules, so never compared with equals.
boolean	merges(IdentifierService names, String columnName) merges(gudusoft.gsqlparser.EDbVendor, String) under one analysis's identifier rules.

Methods inherited from class Object

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

Constructor Detail

UsingMerge

public UsingMerge(EJoinType joinType)

Method Detail

addColumnName

public void addColumnName(String name)

addParticipant

public void addParticipant(TTable table)

Participants are added LEFT side first, right side last, and the order is meaningful.

merges

public boolean merges(EDbVendor vendor,
                      String columnName)

Identifiers fold by the vendor's rules, so never compared with equals.

merges

public boolean merges(IdentifierService names,
                      String columnName)

merges(gudusoft.gsqlparser.EDbVendor, String) under one analysis's identifier rules.

hasParticipant

public boolean hasParticipant(TTable table)

getParticipants

public List<TTable> getParticipants()

getJoinType

public EJoinType getJoinType()