SQLFunction、 SQLFunctionTemplate

org.hibernate.dialect.function 
Interface SQLFunction

All Known Implementing Classes:

AbstractAnsiTrimEmulationFunction, AnsiTrimEmulationFunction, AnsiTrimFunction, AvgFunction, AvgWithArgumentCastFunction, CastFunction,CharIndexFunction, ClassicAvgFunction, ClassicCountFunction, ClassicSumFunction, ConditionalParenthesisFunction, ConvertFunction,DerbyConcatFunction, NoArgSQLFunction, NvlFunction, PositionSubstringFunction, SQLFunctionTemplate, StandardJDBCEscapeFunction,StandardSQLFunction, TrimFunctionTemplate, VarArgsSQLFunction

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public interface SQLFunction

Provides support routines(常规) for the HQL functions as used in the various（各种） SQL Dialects Provides an interface for supporting various HQL functions that are translated（翻译） to SQL. The Dialect and its sub-classes use this interface to provide details required(必须的) for processing(处理) of the function.

org.hibernate.dialect.function 
Class SQLFunctionTemplate

java.lang.Object  org.hibernate.dialect.function.SQLFunctionTemplate

All Implemented Interfaces:

SQLFunction

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public class SQLFunctionTemplate
extends Object
implements SQLFunction

Represents HQL functions that can have different representations(表现) in different SQL dialects. E.g. in HQL we can define function concat(?1, ?2) to concatenate(连接) two strings p1 and p2. Target(规定) SQL function will be dialect-specific, e.g. (?1 || ?2) for Oracle, concat(?1, ?2) for MySql, (?1 + ?2) for MS SQL. Each dialect will define a template(模板) as a string (exactly like above) marking function parameters with '?' followed by parameter's index (first index is 1).