A predicate contains instructions for filtering rows when performing a Query.
Predicates currently are the WHERE clause in a SQL statement and are used verbatim by the PersistentStore. In general, you should use Query.where instead of using this class directly, as Query.where will use the underlying PersistentStore to generate a QueryPredicate for you.
A predicate has a format and parameters. The format is the String
that comes after WHERE in a SQL query. The format may
have parameterized values, for which the corresponding value is in the parameters map. A parameter is prefixed with '@' in the format string. Currently,
the format string's parameter syntax is defined by the PersistentStore it is used on. An example of that format:
var predicate = new QueryPredicate("x = @xValue", {"xValue" : 5});
Static Methods
-
andPredicates(
Iterable<QueryPredicate> predicates) → QueryPredicate -
Joins together a list of predicates by the 'and' token.
Constructors
- QueryPredicate(String format, Map<String, dynamic> parameters)
-
Default constructor
Properties
- format → String
-
The string format of the this predicate.
read / write - parameters → Map<String, dynamic>
-
A map of values to replace in the format string at execution time.
read / write - hashCode → int
-
The hash code for this object.
read-only, inherited - runtimeType → Type
-
A representation of the runtime type of the object.
read-only, inherited
Operators
-
operator ==(
other) → bool -
The equality operator.
inherited
Methods
-
noSuchMethod(
Invocation invocation) → dynamic -
Invoked when a non-existent method or property is accessed.
inherited -
toString(
) → String -
Returns a string representation of this object.
inherited