Class MapSizeMethod
- java.lang.Object
-
- org.datanucleus.store.rdbms.sql.method.MapSizeMethod
-
- All Implemented Interfaces:
SQLMethod
public class MapSizeMethod extends java.lang.Object implements SQLMethod
Method for evaluating {mapExpr}.size(). Returns a NumericExpression. Equates to a sub-query on the table for the map returning the COUNT(*) of the number of entries. Something likeSELECT COUNT(*) FROM MAPTABLE A0_SUB WHERE A0_SUB.OWNER_ID_OID = A0.OWNER_ID
where A0 is the candidate table in the outer query, and MAPTABLE is the join table (if using join map) or the key/value table (if using FK map).
-
-
Constructor Summary
Constructors Constructor Description MapSizeMethod()
-
Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description SQLExpression
getExpression(SQLStatement stmt, SQLExpression expr, java.util.List<SQLExpression> args)
Return the expression for this SQL function.
-
-
-
Method Detail
-
getExpression
public SQLExpression getExpression(SQLStatement stmt, SQLExpression expr, java.util.List<SQLExpression> args)
Description copied from interface:SQLMethod
Return the expression for this SQL function.- Specified by:
getExpression
in interfaceSQLMethod
- Parameters:
stmt
- SQLStatement that this expression is forexpr
- The expression that it is invoked onargs
- Arguments passed in- Returns:
- The SQL expression using the SQL function
-
-