Query Expressions

Query Expression #

Query expression is used to execute queries and scans over items in the DynamoDB table. Such expressions can also be used in other areas of Dynamo-Browse, such as populating the value of new columns.

Note that the query expression language is still under early development and may change in the future.

The expression is represented in EBNF form:

string              = '"' .* '"';

identifier          = [a-zA-Z_][a-zA-Z0-9_]*;

literal             = string;

field               = identifier ("." identifier)*;

binary_operation    = field ( "=" | "^=" ) literal;

expression          = field
                    | binary_operation
                    | expr ( "and" | "or" ) expr

The order of operations, from lowest priority to highest priority are as follows:

Operation Symbol
Disjunction or
Conjunction and
Equality =, ^=

The types of binary operations that are supported are:

  • attr = "value": matches items where attribute attr matches the string value
  • attr ^= "value": matches items where attribute attr has the prefix value