Uses of Package
org.eclipse.persistence.jpa.jpql.tools.model.query

Packages that use org.eclipse.persistence.jpa.jpql.tools.model.query

Package	Description
org.eclipse.persistence.jpa.jpql.tools
org.eclipse.persistence.jpa.jpql.tools.model	The classes defined in this package define the state model API, a state model can be used to manually or programmatically create and edit a JPQL query.
org.eclipse.persistence.jpa.jpql.tools.model.query	This package contains the StateObject classes that represents a JPQL query.

Classes in org.eclipse.persistence.jpa.jpql.tools.model.query used by org.eclipse.persistence.jpa.jpql.tools

Class and Description
AbstractPathExpressionStateObject An identification variable followed by the navigation operator (.) and a state field or association field is a path expression.
AbstractSchemaNameStateObject An abstract schema name designates the abstract schema type over which the query ranges.
AbstractTraverseChildrenVisitor This StateObjectVisitor traverses the entire hierarchy of the JPQL parsed tree by going down into each of the children of any given StateObject.
AnonymousStateObjectVisitor This visitor allows a subclass to simply override AnonymousStateObjectVisitor.visit(StateObject) and perform the same task for all visited ItateObjects.
CollectionValuedPathExpressionStateObject A collection-valued field is designated by the name of an association field in a one-to-many or a many-to-many relationship or by the name of an element collection field.
ConstructorExpressionStateObject In the SELECT clause a constructor may be used in the SELECT list to return one or more Java instances.
EntityTypeLiteralStateObject This StateObject wraps the name of an entity type.
IdentificationVariableStateObject This state object represents a single identification variable, which is identifying TODO.
JPQLQueryStateObject This is the root of the StateObject hierarchy that represents a JPQL query.
OrderByItemStateObject An ORDER BY item must be one of the following: A state_field_path_expression that evaluates to an orderable state field of an entity or embeddable class abstract schema type designated in the SELECT clause by one of the following: A general_identification_variable A single_valued_object_path_expression A state_field_path_expression that evaluates to the same state field of the same entity or embeddable abstract schema type as a state_field_path_expression in the SELECT clause A result_variable that refers to an orderable item in the SELECT clause for which the same result_variable has been specified.
ResultVariableStateObject A result variable may be used to name a select item in the query result.
SelectStatementStateObject This state object represents a select statement, which has at least a SELECT clause and a FROM clause.
StateFieldPathExpressionStateObject A single-valued association field is designated by the name of an association-field in a one-to-one or many-to-one relationship.
StateObject A StateObject is an editable representation of a JPQL query.
StateObjectVisitor The visitor is used to traverse the StateObject hierarchy that represents a JPQL query.
TreatExpressionStateObject Returns an expression that allows to treat its base as if it were a subclass of the class returned by the base.

Classes in org.eclipse.persistence.jpa.jpql.tools.model.query used by org.eclipse.persistence.jpa.jpql.tools.model

Class and Description
AbsExpressionStateObject The ABS function removes the minus sign from a specified argument and returns the absolute value, which is always a positive number or zero.
AbstractConditionalClauseStateObject Conditional expressions are composed of other conditional expressions, comparison operations, logical operations, path expressions that evaluate to boolean values, boolean literals, and boolean input parameters.
AbstractDoubleEncapsulatedExpressionStateObject This StateObject represents a JPQL expression that has a JPQL identifier followed by two an encapsulated expression with parenthesis, the two expression are separated by a comma.
AbstractFromClauseStateObject This state object represents the abstract definition of a FROM clause, which is either the FROM clause of the query or of a sub-query expression.
AbstractIdentificationVariableDeclarationStateObject
AbstractModifyStatementStateObject The abstract definition of a modify statement.
AbstractPathExpressionStateObject An identification variable followed by the navigation operator (.) and a state field or association field is a path expression.
AbstractRangeVariableDeclarationStateObject
AbstractSchemaNameStateObject An abstract schema name designates the abstract schema type over which the query ranges.
AbstractSelectClauseStateObject This state object represents the abstract definition of a SELECT clause, which is either the SELECT clause of the top-level query or of a subquery.
AbstractSelectStatementStateObject This state object represents the select statement, which has at least a SELECT clause and a FROM clause.
AbstractSingleEncapsulatedExpressionStateObject This StateObject represents a JPQL expression that has a JPQL identifier followed by an encapsulated expression with parenthesis.
AbstractTripleEncapsulatedExpressionStateObject This state object takes care of parsing an expression that encapsulates three expressions separated by a comma.
AdditionExpressionStateObject TODO: BNF: arithmetic_expression ::= arithmetic_expression + arithmetic_term
AggregateFunctionStateObject In the SELECT clause the result of a query may be the result of an aggregate function applied to a path expression.
AllOrAnyExpressionStateObject An ALL conditional expression is a predicate that is true if the comparison operation is true for all values in the result of the subquery or the result of the subquery is empty.
AndExpressionStateObject The AND logical operator chains multiple criteria together.
ArithmeticFactorStateObject This state object simply adds a plus or minus sign to the arithmetic primary expression.
AvgFunctionStateObject One of the aggregate functions.
BadExpressionStateObject This wraps an invalid portion of the JPQL query that could not be parsed.
BetweenExpressionStateObject Used in conditional expression to determine whether the result of an expression falls within an inclusive range of values.
CaseExpressionStateObject A CASE predicate is used to calculate a condition and when it's true, its THEN expression will be executed.
CoalesceExpressionStateObject A COALESCE expression returns null if all its arguments evaluate to null, and the value of the first non-null argument otherwise.
CollectionMemberDeclarationStateObject An identification variable declared by a collection_member_declaration ranges over values of a collection obtained by navigation using a path expression.
CollectionMemberExpressionStateObject This expression tests whether the designated value is a member of the collection specified by the collection-valued path expression.
CollectionValuedPathExpressionStateObject A collection-valued field is designated by the name of an association field in a one-to-many or a many-to-many relationship or by the name of an element collection field.
ComparisonExpressionStateObject Only the values of like types are permitted to be compared.
CompoundExpressionStateObject A compound StateObject has a left and right expressions combined by an identifier.
ConcatExpressionStateObject The CONCAT function returns a string that is a concatenation of its arguments.
ConstructorExpressionStateObject In the SELECT clause a constructor may be used in the SELECT list to return one or more Java instances.
CountFunctionStateObject One of the aggregate functions.
DateTimeStateObject This DateTimeStateObject represents a date or time.
DeleteClauseStateObject This is the DELETE clause of the DELETE statement.
DeleteStatementStateObject Bulk delete operation apply to entities of a single entity class (together with its subclasses, if any).
DerivedPathIdentificationVariableDeclarationStateObject
DerivedPathVariableDeclarationStateObject BNF: subselect_identification_variable_declaration ::= derived_path_expression [AS] identification_variable {join}*
DivisionExpressionStateObject TODO: BNF: arithmetic_expression ::= arithmetic_expression / arithmetic_term
EclipseLinkStateObjectVisitor The interface is used to traverse the StateObject hierarchy that represents a JPQL query as well as what EclipseLink adds on top of the basic grammar.
EmptyCollectionComparisonExpressionStateObject This expression tests whether or not the collection designated by the collection-valued path expression is empty (i.e, has no elements).
EncapsulatedIdentificationVariableExpressionStateObject This object represents an identification variable that is wrapped by a function.
EntityTypeLiteralStateObject This StateObject wraps the name of an entity type.
EntryExpressionStateObject This object represents an identification variable that maps the Map.Entry) of a Map.
EnumTypeStateObject This StateObject wraps the name of an Enum constant.
ExistsExpressionStateObject An EXISTS expression is a predicate that is true only if the result of the subquery consists of one or more values and that is false otherwise.
FromClauseStateObject The FROM clause of a query defines the domain of the query by declaring identification variables.
FunctionExpressionStateObject
GroupByClauseStateObject The GROUP BY construct enables the aggregation of values according to the properties of an entity class.
HavingClauseStateObject The HAVING construct enables conditions to be specified that further restrict the query result as restrictions upon the groups.
IdentificationVariableDeclarationStateObject An identification variable is a valid identifier declared in the FROM clause of a query.
IdentificationVariableStateObject This state object represents a single identification variable, which is identifying TODO.
IndexExpressionStateObject The INDEX function returns an integer value corresponding to the position of its argument in an ordered list.
InExpressionStateObject The state field path expression must have a string, numeric, or enum value.
InputParameterStateObject Either positional or named parameters may be used.
JoinStateObject A JOIN enables the fetching of an association as a side effect of the execution of a query.
JPQLQueryStateObject This is the root of the StateObject hierarchy that represents a JPQL query.
KeyExpressionStateObject This object represents an identification variable that maps the keys of a Map.
KeywordExpressionStateObject The expression representing some keywords: TRUE, FALSE or NULL.
LengthExpressionStateObject The LENGTH function returns the length of the string in characters as an integer.
LikeExpressionStateObject The LIKE condition is used to specify a search for a pattern.
ListHolderStateObject A ListHolderStateObject is a StateObject having a list of children and this gives access to some operation over the list.
LocateExpressionStateObject The LOCATE function returns the position of a given string within a string, starting the search at a specified position.
LowerExpressionStateObject The LOWER function converts a string to lower case and it returns a string.
MaxFunctionStateObject One of the aggregate functions.
MinFunctionStateObject One of the aggregate functions.
ModExpressionStateObject The modulo operation finds the remainder of division of one number by another.
MultiplicationExpressionStateObject TODO: BNF: arithmetic_expression ::= arithmetic_expression * arithmetic_term
NotExpressionStateObject BNF: expression ::= NOT conditional_primary
NullComparisonExpressionStateObject A null comparison tests whether or not the single-valued path expression or input parameter is a NULL value.
NullIfExpressionStateObject NULLIF returns the first expression if the two expressions are not equal.
NumericLiteralStateObject Exact numeric literals support the use of Java integer literal syntax as well as SQL exact numeric literal syntax.
ObjectExpressionStateObject Stand-alone identification variables in the SELECT clause may optionally be qualified by the OBJECT operator.
OrderByClauseStateObject The ORDER BY clause allows the objects or values that are returned by the query to be ordered.
OrderByItemStateObject An ORDER BY item must be one of the following: A state_field_path_expression that evaluates to an orderable state field of an entity or embeddable class abstract schema type designated in the SELECT clause by one of the following: A general_identification_variable A single_valued_object_path_expression A state_field_path_expression that evaluates to the same state field of the same entity or embeddable abstract schema type as a state_field_path_expression in the SELECT clause A result_variable that refers to an orderable item in the SELECT clause for which the same result_variable has been specified.
OrExpressionStateObject The OR logical operator chains multiple criteria together.
RangeVariableDeclarationStateObject Range variable declarations allow the developer to designate a "root" for objects which may not be reachable by navigation.
ResultVariableStateObject A result variable may be used to name a select item in the query result.
SelectClauseStateObject The SELECT statement queries data from entities, which determines the type of the objects or values to be selected.
SelectStatementStateObject This state object represents a select statement, which has at least a SELECT clause and a FROM clause.
SimpleFromClauseStateObject The FROM clause of a sub-query defines the domain of the sub-query by declaring identification variables.
SimpleSelectClauseStateObject The SELECT statement queries data from entities.
SimpleSelectStatementStateObject This state object represents a subquery, which has at least a SELECT clause and a FROM clause.
SimpleStateObject This StateObject simply holds onto a string.
SizeExpressionStateObject The SIZE function returns an integer value, the number of elements of the collection.
SqrtExpressionStateObject The SQRT function takes a numeric argument and returns a Double.
StateFieldPathExpressionStateObject A single-valued association field is designated by the name of an association-field in a one-to-one or many-to-one relationship.
StateObject A StateObject is an editable representation of a JPQL query.
StateObjectVisitor The visitor is used to traverse the StateObject hierarchy that represents a JPQL query.
StringLiteralStateObject A string literal is enclosed in single quotes.
SubExpressionStateObject This expression wraps a sub-expression within parenthesis.
SubstringExpressionStateObject The second and third arguments of the SUBSTRING function denote the starting position and length of the substring to be returned.
SubtractionExpressionStateObject TODO: BNF: arithmetic_expression ::= arithmetic_expression - arithmetic_term
SumFunctionStateObject One of the aggregate functions.
TreatExpressionStateObject Returns an expression that allows to treat its base as if it were a subclass of the class returned by the base.
TrimExpressionStateObject The TRIM function trims the specified character from a string.
TypeExpressionStateObject An entity type expression can be used to restrict query polymorphism.
UnknownExpressionStateObject This StateObject holds onto an unknown portion of a JPQL query that could not be parsed.
UpdateClauseStateObject This is the UPDATE clause of the UPDATE statement.
UpdateItemStateObject The new_value specified for an update operation must be compatible in type with the field to which it is assigned.
UpdateStatementStateObject The UPDATE clause of a query consists of a conditional expression used to select objects or values that satisfy the expression.
UpperExpressionStateObject The UPPER function converts a string to upper case and it returns a string.
ValueExpressionStateObject This object represents an identification variable that maps the values of a Map.
WhenClauseStateObject A WHEN predicate is used to calculate a condition and when it's true, its THEN will be executed.
WhereClauseStateObject The WHERE clause of a query consists of a conditional expression used to select objects or values that satisfy the expression.

Classes in org.eclipse.persistence.jpa.jpql.tools.model.query used by org.eclipse.persistence.jpa.jpql.tools.model.query

Class and Description
AbsExpressionStateObject The ABS function removes the minus sign from a specified argument and returns the absolute value, which is always a positive number or zero.
AbstractConditionalClauseStateObject Conditional expressions are composed of other conditional expressions, comparison operations, logical operations, path expressions that evaluate to boolean values, boolean literals, and boolean input parameters.
AbstractDoubleEncapsulatedExpressionStateObject This StateObject represents a JPQL expression that has a JPQL identifier followed by two an encapsulated expression with parenthesis, the two expression are separated by a comma.
AbstractEncapsulatedExpressionStateObject This expression handles parsing the identifier followed by an expression encapsulated within parenthesis.
AbstractFromClauseStateObject This state object represents the abstract definition of a FROM clause, which is either the FROM clause of the query or of a sub-query expression.
AbstractIdentificationVariableDeclarationStateObject
AbstractListHolderStateObject The abstraction definition of a StateObject that holds onto a list of children, the methods defined in ListHolderStateObject are automatically handled here.
AbstractModifyClauseStateObject
AbstractModifyStatementStateObject The abstract definition of a modify statement.
AbstractPathExpressionStateObject An identification variable followed by the navigation operator (.) and a state field or association field is a path expression.
AbstractRangeVariableDeclarationStateObject
AbstractSchemaNameStateObject An abstract schema name designates the abstract schema type over which the query ranges.
AbstractSelectClauseStateObject This state object represents the abstract definition of a SELECT clause, which is either the SELECT clause of the top-level query or of a subquery.
AbstractSelectStatementStateObject This state object represents the select statement, which has at least a SELECT clause and a FROM clause.
AbstractSingleEncapsulatedExpressionStateObject This StateObject represents a JPQL expression that has a JPQL identifier followed by an encapsulated expression with parenthesis.
AbstractStateObject The abstract definition of a StateObject.
AbstractStateObjectVisitor The abstract definition of StateObjectVisitor, which implements all the methods but does nothing.
AbstractTripleEncapsulatedExpressionStateObject This state object takes care of parsing an expression that encapsulates three expressions separated by a comma.
AdditionExpressionStateObject TODO: BNF: arithmetic_expression ::= arithmetic_expression + arithmetic_term
AggregateFunctionStateObject In the SELECT clause the result of a query may be the result of an aggregate function applied to a path expression.
AllOrAnyExpressionStateObject An ALL conditional expression is a predicate that is true if the comparison operation is true for all values in the result of the subquery or the result of the subquery is empty.
AndExpressionStateObject The AND logical operator chains multiple criteria together.
AnonymousStateObjectVisitor This visitor allows a subclass to simply override AnonymousStateObjectVisitor.visit(StateObject) and perform the same task for all visited ItateObjects.
AnonynousEclipseLinkStateObjectVisitor This visitor allows a subclass to simply override AnonymousStateObjectVisitor.visit(StateObject) and perform the same task for all visited ItateObjects.
ArithmeticExpressionStateObject This expression represents an arithmetic expression, which means the first and second expressions are aggregated with an arithmetic sign.
ArithmeticFactorStateObject This state object simply adds a plus or minus sign to the arithmetic primary expression.
AvgFunctionStateObject One of the aggregate functions.
BadExpressionStateObject This wraps an invalid portion of the JPQL query that could not be parsed.
BetweenExpressionStateObject Used in conditional expression to determine whether the result of an expression falls within an inclusive range of values.
CaseExpressionStateObject A CASE predicate is used to calculate a condition and when it's true, its THEN expression will be executed.
ChangeSupport This ChangeSupport is responsible to notifies registered listeners upon changes made to a StateObject, those changes are either a property has changed (IPropertyChangeListener) or the content of a list has changed (IListChangeListener).
CoalesceExpressionStateObject A COALESCE expression returns null if all its arguments evaluate to null, and the value of the first non-null argument otherwise.
CollectionExpressionStateObject This StateObject is a temporary object used to store a list of StateObjects.
CollectionMemberDeclarationStateObject An identification variable declared by a collection_member_declaration ranges over values of a collection obtained by navigation using a path expression.
CollectionMemberExpressionStateObject This expression tests whether the designated value is a member of the collection specified by the collection-valued path expression.
CollectionValuedPathExpressionStateObject A collection-valued field is designated by the name of an association field in a one-to-many or a many-to-many relationship or by the name of an element collection field.
ComparisonExpressionStateObject Only the values of like types are permitted to be compared.
CompoundExpressionStateObject A compound StateObject has a left and right expressions combined by an identifier.
ConcatExpressionStateObject The CONCAT function returns a string that is a concatenation of its arguments.
ConstructorExpressionStateObject In the SELECT clause a constructor may be used in the SELECT list to return one or more Java instances.
CountFunctionStateObject One of the aggregate functions.
DateTimeStateObject This DateTimeStateObject represents a date or time.
DeclarationStateObject This defines the declaration portion of a query, which is the FROM clause of a query.
DeleteClauseStateObject This is the DELETE clause of the DELETE statement.
DeleteStatementStateObject Bulk delete operation apply to entities of a single entity class (together with its subclasses, if any).
DerivedPathIdentificationVariableDeclarationStateObject
DerivedPathVariableDeclarationStateObject BNF: subselect_identification_variable_declaration ::= derived_path_expression [AS] identification_variable {join}*
DivisionExpressionStateObject TODO: BNF: arithmetic_expression ::= arithmetic_expression / arithmetic_term
EclipseLinkStateObjectVisitor The interface is used to traverse the StateObject hierarchy that represents a JPQL query as well as what EclipseLink adds on top of the basic grammar.
EmptyCollectionComparisonExpressionStateObject This expression tests whether or not the collection designated by the collection-valued path expression is empty (i.e, has no elements).
EncapsulatedIdentificationVariableExpressionStateObject This object represents an identification variable that is wrapped by a function.
EntityTypeLiteralStateObject This StateObject wraps the name of an entity type.
EntryExpressionStateObject This object represents an identification variable that maps the Map.Entry) of a Map.
EnumTypeStateObject This StateObject wraps the name of an Enum constant.
ExistsExpressionStateObject An EXISTS expression is a predicate that is true only if the result of the subquery consists of one or more values and that is false otherwise.
FromClauseStateObject The FROM clause of a query defines the domain of the query by declaring identification variables.
FunctionExpressionStateObject
GroupByClauseStateObject The GROUP BY construct enables the aggregation of values according to the properties of an entity class.
HavingClauseStateObject The HAVING construct enables conditions to be specified that further restrict the query result as restrictions upon the groups.
IdentificationVariableDeclarationStateObject An identification variable is a valid identifier declared in the FROM clause of a query.
IdentificationVariableStateObject This state object represents a single identification variable, which is identifying TODO.
IndexExpressionStateObject The INDEX function returns an integer value corresponding to the position of its argument in an ordered list.
InExpressionStateObject The state field path expression must have a string, numeric, or enum value.
InputParameterStateObject Either positional or named parameters may be used.
JoinStateObject A JOIN enables the fetching of an association as a side effect of the execution of a query.
JPQLQueryStateObject This is the root of the StateObject hierarchy that represents a JPQL query.
KeyExpressionStateObject This object represents an identification variable that maps the keys of a Map.
KeywordExpressionStateObject The expression representing some keywords: TRUE, FALSE or NULL.
LengthExpressionStateObject The LENGTH function returns the length of the string in characters as an integer.
LikeExpressionStateObject The LIKE condition is used to specify a search for a pattern.
ListHolderStateObject A ListHolderStateObject is a StateObject having a list of children and this gives access to some operation over the list.
LocateExpressionStateObject The LOCATE function returns the position of a given string within a string, starting the search at a specified position.
LogicalExpressionStateObject This expression represents a logical expression, which means the first and second expressions are aggregated with either the AND or the OR operator.
LowerExpressionStateObject The LOWER function converts a string to lower case and it returns a string.
MaxFunctionStateObject One of the aggregate functions.
MinFunctionStateObject One of the aggregate functions.
ModExpressionStateObject The modulo operation finds the remainder of division of one number by another.
MultiplicationExpressionStateObject TODO: BNF: arithmetic_expression ::= arithmetic_expression * arithmetic_term
NotExpressionStateObject BNF: expression ::= NOT conditional_primary
NullComparisonExpressionStateObject A null comparison tests whether or not the single-valued path expression or input parameter is a NULL value.
NullIfExpressionStateObject NULLIF returns the first expression if the two expressions are not equal.
NumericLiteralStateObject Exact numeric literals support the use of Java integer literal syntax as well as SQL exact numeric literal syntax.
ObjectExpressionStateObject Stand-alone identification variables in the SELECT clause may optionally be qualified by the OBJECT operator.
OrderByClauseStateObject The ORDER BY clause allows the objects or values that are returned by the query to be ordered.
OrderByItemStateObject An ORDER BY item must be one of the following: A state_field_path_expression that evaluates to an orderable state field of an entity or embeddable class abstract schema type designated in the SELECT clause by one of the following: A general_identification_variable A single_valued_object_path_expression A state_field_path_expression that evaluates to the same state field of the same entity or embeddable abstract schema type as a state_field_path_expression in the SELECT clause A result_variable that refers to an orderable item in the SELECT clause for which the same result_variable has been specified.
OrExpressionStateObject The OR logical operator chains multiple criteria together.
RangeVariableDeclarationStateObject Range variable declarations allow the developer to designate a "root" for objects which may not be reachable by navigation.
ResultVariableStateObject A result variable may be used to name a select item in the query result.
SelectClauseStateObject The SELECT statement queries data from entities, which determines the type of the objects or values to be selected.
SelectStatementStateObject This state object represents a select statement, which has at least a SELECT clause and a FROM clause.
SimpleFromClauseStateObject The FROM clause of a sub-query defines the domain of the sub-query by declaring identification variables.
SimpleSelectClauseStateObject The SELECT statement queries data from entities.
SimpleSelectStatementStateObject This state object represents a subquery, which has at least a SELECT clause and a FROM clause.
SimpleStateObject This StateObject simply holds onto a string.
SizeExpressionStateObject The SIZE function returns an integer value, the number of elements of the collection.
SqrtExpressionStateObject The SQRT function takes a numeric argument and returns a Double.
StateFieldPathExpressionStateObject A single-valued association field is designated by the name of an association-field in a one-to-one or many-to-one relationship.
StateObject A StateObject is an editable representation of a JPQL query.
StateObjectVisitor The visitor is used to traverse the StateObject hierarchy that represents a JPQL query.
StringLiteralStateObject A string literal is enclosed in single quotes.
SubExpressionStateObject This expression wraps a sub-expression within parenthesis.
SubstringExpressionStateObject The second and third arguments of the SUBSTRING function denote the starting position and length of the substring to be returned.
SubtractionExpressionStateObject TODO: BNF: arithmetic_expression ::= arithmetic_expression - arithmetic_term
SumFunctionStateObject One of the aggregate functions.
TreatExpressionStateObject Returns an expression that allows to treat its base as if it were a subclass of the class returned by the base.
TrimExpressionStateObject The TRIM function trims the specified character from a string.
TypeExpressionStateObject An entity type expression can be used to restrict query polymorphism.
UnknownExpressionStateObject This StateObject holds onto an unknown portion of a JPQL query that could not be parsed.
UpdateClauseStateObject This is the UPDATE clause of the UPDATE statement.
UpdateItemStateObject The new_value specified for an update operation must be compatible in type with the field to which it is assigned.
UpdateStatementStateObject The UPDATE clause of a query consists of a conditional expression used to select objects or values that satisfy the expression.
UpperExpressionStateObject The UPPER function converts a string to upper case and it returns a string.
ValueExpressionStateObject This object represents an identification variable that maps the values of a Map.
VariableDeclarationStateObject This defines a variable declaration, which has a "root" object and an identification variable.
WhenClauseStateObject A WHEN predicate is used to calculate a condition and when it's true, its THEN will be executed.
WhereClauseStateObject The WHERE clause of a query consists of a conditional expression used to select objects or values that satisfy the expression.