6.3 Dynamic Rules

Dynamic rules generate SQL conditions, expand collections and create bound values from fragment arguments. They work inside selectSql, insertSql, updateSql, deleteSql and executeSql fragments.

Start with a query

hint FRAGMENT_SQL_OPEN_PACKAGE = 'off';
hint FRAGMENT_SQL_COLUMN_CASE = 'lower';
var find = @@selectSql(name, minAge)<%
    SELECT id, name FROM people WHERE 1 = 1
    @{ifand, name != null and name != '', name = #{name}}
    @{ifand, minAge != null, age >= #{minAge}}
    ORDER BY id
%>;
return find(null, 30);

The null name omits the name condition. minAge = 30 generates AND age >= ?, with 30 bound through JDBC. Use the sample table in SQL Execution. For a SQL-type API in Dataway, enter the fragment body directly; its arguments come from the request.

Syntax

@{ruleName, content}
@{ruleName, condition, content}

Rule names are case-insensitive. Conditions use OGNL and reference names directly, such as age >= 18. Use #{age} to bind a value inside SQL. These rules belong to SQL fragments; functions and expressions outside the fragment use DataQL syntax.

Content can contain nested rules. Markers inside single-quoted strings, double-quoted text and SQL comments remain literal text.

Reading guide

• Statement Generation Rules: conditions, collections, branches, macros and generated arguments.
• Nested Rules: combine rules and understand evaluation order.
• Custom SQL Rules: implement SqlRule and register it in Dataway.
• XML Dynamic SQL: use tags for longer conditions and loops.

Processing query results

Dynamic rules run before SQL execution. Configure result unpacking, column-name conversion and bindOut through Results and Keys; see Procedures and Multiple Results for procedure outputs. The SQL executor does not register dbVisitor's resultSet, resultUpdate or defaultResult rules, so those rules cannot be copied into a fragment.