EJB query: BNF syntax
The Backus-Naur Form (BNF) is one of the most commonly used notations for specifying the syntax of programming languages or command sets. This article lists the syntax for Enterprise JavaBeans (EJB) query language.
EJB QL ::= [select_clause] from_clause [where_clause] [order_by_clause]
DYNAMIC EJB QL := query_expression [order_by_clause]
query_expression := query_term [UNION [ALL] query_term]*
query_term := {select_clause_dynamic from_clause [where_clause]
[group_by_clause] [having_clause] } | (query_expression) } [order_by_clause]
from_clause::=FROM identification_variable_declaration
[, {identification_variable_declaration | collection_member_declaration } ]*
identification_variable_declaration::=collection_member_declaration |
range_variable_declaration [join]*
join := [ { LEFT [OUTER] | INNER }] JOIN {collection_valued_path_expression | single_valued_path_expression}
[AS] identifier
collection_member_declaration::=
IN ( collection_valued_path_expression ) [AS] identifier
range_variable_declaration::=abstract_schema_name [AS] identifier
single_valued_path_expression ::=
{single_valued_navigation | identification_variable}. ( cmp_field |
method | cmp_field.value_object_attribute | cmp_field.value_object_method )
| single_valued_navigation
single_valued_navigation::=
identification_variable.[ single_valued_cmr_field. ]*
single_valued_cmr_field
collection_valued_path_expression ::=
identification_variable.[ single_valued_cmr_field. ]*
collection_valued_cmr_field
select_clause::= SELECT { ALL | DISTINCT } {single_valued_path_expression |
identification_variable | OBJECT ( identification_variable) |
aggregate_functions }
select_clause_dynamic ::= SELECT { ALL | DISTINCT } [ selection , ]* selection
selection ::= { expression | subselect } [[AS] id ]
order_by_clause::= ORDER BY [ {single_valued_path_expression | integer} [ASC|DESC],]*
{single_valued_path_expression | integer}[ASC|DESC]
where_clause::= WHERE conditional_expression
conditional_expression ::= conditional_term |
conditional_expression OR conditional_term
conditional_term ::= conditional_factor |
conditional_term AND conditional_factor
conditional_factor ::= [NOT] conditional_primary
conditional_primary::=simple_cond_expression | (conditional_expression)
simple_cond_expression ::= comparison_expression | between_expression |
like_expression | in_expression | null_comparison_expression |
empty_collection_comparison_expression | quantified_expression |
exists_expression | is_of_type_expression | collection_member_expression
between_expression ::= expression [NOT] BETWEEN expression AND expression
in_expression ::= single_valued_path_expression [NOT] IN
{ (subselect) | ( [ atom ,]* atom ) }
atom = { string-literal | numeric-constant | input-parameter }
like_expression ::= expression [NOT] LIKE
{string_literal | input_parameter}
[ESCAPE {string_literal | input_parameter}]
null_comparison_expression ::=
single_valued_path_expression IS [ NOT ] NULL
empty_collection_comparison_expression ::=
collection_valued_path_expression IS [NOT] EMPTY
collection_member_expression ::=
{ single_valued_path_expression | input_paramter } [ NOT ] MEMBER [ OF ]
collection_valued_path_expression
quantified_expression ::=
expression comparison_operator {SOME | ANY | ALL} (subselect)
exists_expression ::= EXISTS {collection_valued_path_expression | (subselect)}
subselect ::= SELECT [{ ALL | DISTINCT }] expression from_clause [where_clause]
[group_by_clause] [having_clause]
group_by_clause::= GROUP BY [single_valued_path_expression,]*
single_valued_path_expression
having_clause ::= HAVING conditional_expression
is_of_type_expression ::= identifier IS OF TYPE
([[ONLY] abstract_schema_name,]* [ONLY] abstract_schema_name)
comparison_expression ::= expression comparison_operator { expression | ( subquery ) }
comparison_operator ::= = | > | >= | < | <= | <>
method ::= method_name( [[expression , ]* expression ] )
expression ::= term | expression {+|-} term
term ::= factor | term {*|/} factor
factor ::= {+|-} primary
primary ::= single_valued_path_expression | literal |
( expression ) | input_parameter | functions | aggregate_functions
aggregate_functions :=
AVG([ALL|DISTINCT] expression) |
COUNT({[ALL|DISTINCT] expression | * | identification_variable }) |
MAX([ALL|DISTINCT] expression) |
MIN([ALL|DISTINCT] expression) |
SUM([ALL|DISTINCT] expression) |
functions ::=
ABS(expression) |
BIGINT(expression) |
CHAR({expression [,{ISO|USA|EUR|JIS}] ) |
CONCAT (expression , expression ) |
DATE(expression) |
DAY({expression ) |
DAYS( expression) |
DECIMAL( expression [,integer[,integer]])
DIGITS( expression) |
DOUBLE( expression ) |
FLOAT( expression) |
HOUR ( expression ) |
INTEGER( expression ) |
LCASE ( expression) |
LENGTH(expression) |
LOCATE( expression, expression [, expression] ) |
MICROSECOND( expression ) |
MINUTE ( expression ) |
MOD ( expression , expression ) |
MONTH( expression ) |
REAL( expression) |
SECOND( expression ) |
SMALLINT( expression ) |
SQRT ( expression) |
SUBSTRING( expression, expression[, expression]) |
TIME( expression ) |
TIMESTAMP( expression ) |
UCASE ( expression) |
YEAR( expression )
xrel := XREL identification_variable . { single_valued_cmr_field | collection_valued_cmr_field }
[ , identification_variable . { single_valued_cmr_field | collection_valued_cmr_field } ]*
EJB Query Restrictions and Exceptions
EJB-QL
Limitation with CMP Inheritance and FROM Clause Joins Usage
The
EJB-QL parser has been found to improperly generate SQL with queries
that match the following cumulative criteria:
- The EJB-QL query contains a join in the FROM clause (For example, FROM Entity a, IN (a.b.c.d) dGroup).
- The EJB-QL query contains a predicate that navigates across an inner path element also associated with the FROM clause join (For example, WHERE a.b.g.id = :?1).
- One or more of the non-leaf path entities in the FROM join utilize entity type inheritance (For example, b extends b_super).
- The entity addressed by the common path element in the predicate also utilizes entity type inheritance (For example, g extends g_super).