Class MapSizeMethod
java.lang.Object
org.datanucleus.store.rdbms.sql.method.MapSizeMethod
- All Implemented Interfaces:
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 like
SELECT COUNT(*) FROM MAPTABLE A0_SUB WHERE A0_SUB.OWNER_ID_OID = A0.OWNER_IDwhere 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).
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptiongetExpression
(SQLStatement stmt, SQLExpression expr, List<SQLExpression> args) Return the expression for this SQL function.
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Constructor Details
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MapSizeMethod
public MapSizeMethod()
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Method Details
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getExpression
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
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