be.SIRAPRISE.server

Class S_LEFTJOINUSING

java.lang.Object

be.SIRAPRISE.typeimplementations.RelationalOperator

be.SIRAPRISE.typeimplementations.LEFTJOINUSING

be.SIRAPRISE.server.S_LEFTJOINUSING

All Implemented Interfaces:

OperatorGenerator, UsingRelationalOperator

public final class S_LEFTJOINUSING
extends LEFTJOINUSING

S_LEFTJOINUSING is the 'USING' version of the "relationally more correct" version of OUTER JOIN. It provides default values for the attributes of the "nonexisting joined-in tuples". The syntax is LEFTJOIN(rexp1,rexp2,(defaultvalueslist)), and is translated to (and implemented as) UNION(JOIN(rexp1,rexp2),EXTEND(SEMIMINUS(rexp1,rexp2),(defaultvalueslist)))

Author:

Erwin Smout

Method Summary

Modifier and Type	Method and Description
RelationalOperatorInvocation	createInvocation(java.util.LinkedList<java.lang.String> arguments, NameIdentifier specialRelvar, be.SIRAPRISE.server.LexicalScopeForNames lexicalscope, java.util.HashMap<java.lang.String,be.SIRAPRISE.server.Expression> parameterDeclarations, boolean tentative, be.SIRAPRISE.server.Luw luw, boolean useOperatorSignaturesCompletion) Creates an invocation object representing the invocation of this operator with the given arguments and lexical scope.
int	getMaximumArgumentCount() This method is duplicated here from the RelationalOperator class to facilitate access to that method through this interface.
int	getMinimumArgumentCount() This method is duplicated here from the RelationalOperator class to facilitate access to that method through this interface.
java.lang.String	getName()

Methods inherited from class be.SIRAPRISE.typeimplementations.LEFTJOINUSING

createInvocation, getOperatorGeneratorSignature

Methods inherited from class be.SIRAPRISE.typeimplementations.RelationalOperator

getMaximumArgumentCount, getMinimumArgumentCount, getName, isMonoRelationOperator, toString

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Method Detail

createInvocation

public RelationalOperatorInvocation createInvocation(java.util.LinkedList<java.lang.String> arguments,
                                                     NameIdentifier specialRelvar,
                                                     be.SIRAPRISE.server.LexicalScopeForNames lexicalscope,
                                                     java.util.HashMap<java.lang.String,be.SIRAPRISE.server.Expression> parameterDeclarations,
                                                     boolean tentative,
                                                     be.SIRAPRISE.server.Luw luw,
                                                     boolean useOperatorSignaturesCompletion)

Creates an invocation object representing the invocation of this operator with the given arguments and lexical scope.

Parameters:

arguments - The textual representation of the first input argument

specialRelvar - The relvar that needs to be given "special treatment" when it is referenced in the compiled expression. The "special treatment" at hand is to replace all references to it with an expression that denotes the post-update value of the relvar (the well-known MINUS(UNION()) sequence. null if there is no such relvar (most cases). Only to be used by the Multiple Assignment updates collecting machinery.

lexicalscope - The lexical scope within which attribute names will have to resolve

parameterDeclarations - The set in which the names of all scalar parameters needed to evaluate this expression will be collected

tentative - flag indicating whether this compile is "tentative" or not. "Tentative" compiles ignore the ServerEngine cache, and read the catalog as if each catalog relvar already had the value that would be left if this luw's (= the luw issuing this compile) had already been in place, that is, as if each catalog relvar already had the value <relvar> UNION INSERTS(<relvar>) MINUS DELETES(<relvar>).

luw - The requesting luw

useOperatorSignaturesCompletion - flag indicating whether to use the operator signatures completion or not. Using the feature can (will) lead to infinite loops while instantiating a UDT type that has a possrep constraint associated with it. The compilation of that expression WITH usage of the signatures features might cause type matching checks, which might cause type instantiation requests, which might be a type instantiation request for the type we are in the process of instantiating already ...

Returns:

An invocation object representing the invocation of this operator with the given arguments

getName

public java.lang.String getName()

Returns:

the name of the operator

getMaximumArgumentCount

public int getMaximumArgumentCount()

This method is duplicated here from the RelationalOperator class to facilitate access to that method through this interface. The strictly clean way to achieve this is to separate interface declaration and implementation at the RelationaLOperator level

Returns:

The maximum syntactic argument count

getMinimumArgumentCount

public int getMinimumArgumentCount()

This method is duplicated here from the RelationalOperator class to facilitate access to that method through this interface. The strictly clean way to achieve this is to separate interface declaration and implementation at the RelationaLOperator level

Returns:

The minimum syntactic argument count