com.orientechnologies.orient.core.sql.functions

Interface OIndexableSQLFunction

All Superinterfaces:

OSQLFunction

public interface OIndexableSQLFunction
extends OSQLFunction

This interface represents SQL functions whose implementation can rely on an index. If used in a WHERE condition, this kind of function can be invoked to retrieve target records from an underlying structure, like an index

Author:

Luigi Dell'Aquila

Method Summary

Modifier and Type	Method and Description
long	estimate(OFromClause target, OBinaryCompareOperator operator, Object rightValue, OCommandContext ctx, OExpression... args) estimates the number of entries returned by searchFromTarget() with these parameters
Iterable<OIdentifiable>	searchFromTarget(OFromClause target, OBinaryCompareOperator operator, Object rightValue, OCommandContext ctx, OExpression... args) returns all the entries belonging to the target that match the binary condition where this function appears

Methods inherited from interface com.orientechnologies.orient.core.sql.functions.OSQLFunction

aggregateResults, config, execute, filterResult, getMaxParams, getMinParams, getName, getResult, getSyntax, mergeDistributedResult, setResult, shouldMergeDistributedResult

Method Detail

searchFromTarget

Iterable<OIdentifiable> searchFromTarget(OFromClause target,
                                         OBinaryCompareOperator operator,
                                         Object rightValue,
                                         OCommandContext ctx,
                                         OExpression... args)

returns all the entries belonging to the target that match the binary condition where this function appears

Parameters:

target - the query target

operator - the operator after the function, eg. in select from Foo where myFunction(name) > 4 the operator is >

rightValue - the value that has to be compared to the function result, eg. in select from Foo where myFunction(name) > 4 the right value is 4

ctx - the command context for this query

args - the function arguments, eg. in select from Foo where myFunction(name) > 4 the arguments are [name]

Returns:

an iterable of records that match the condition; null means that the execution could not be performed for some reason.

estimate

long estimate(OFromClause target,
              OBinaryCompareOperator operator,
              Object rightValue,
              OCommandContext ctx,
              OExpression... args)

estimates the number of entries returned by searchFromTarget() with these parameters

Parameters:

target - the query target

operator - the operator after the function, eg. in select from Foo where myFunction(name) > 4 the operator is >

rightValue - the value that has to be compared to the function result, eg. in select from Foo where myFunction(name) > 4 the right value is 4

ctx - the command context for this query

args - the function arguments, eg. in select from Foo where myFunction(name) > 4 the arguments are [name]

Returns:

an estimantion of how many entries will be returned by searchFromTarget() with these parameters, -1 if the estimation cannot be done