程序包 org.hibernate.dialect.pagination

类 LegacyLimitHandler

java.lang.Object

org.hibernate.dialect.pagination.AbstractLimitHandler

org.hibernate.dialect.pagination.LegacyLimitHandler

所有已实现的接口:

LimitHandler

public class LegacyLimitHandler
extends AbstractLimitHandler

Limit handler that delegates all operations to the underlying dialect.

作者:

Lukasz Antoniak (lukasz dot antoniak at gmail dot com)

构造器概要

构造器

构造器	说明
LegacyLimitHandler(Dialect dialect)	Constructs a LegacyLimitHandler

方法概要

修饰符和类型	方法	说明
boolean	bindLimitParametersFirst()	Does the LIMIT clause come at the start of the SELECT statement, rather than at the end?
boolean	bindLimitParametersInReverseOrder()	ANSI SQL defines the LIMIT clause to be in the form LIMIT offset, limit.
int	convertToFirstRowValue(int zeroBasedFirstResult)	Hibernate APIs explicitly state that setFirstResult() should be a zero-based offset.
boolean	forceLimitUsage()	Generally, if there is no limit applied to a Hibernate query we do not apply any limits to the SQL query.
String	processSql(String sql, RowSelection selection)	Return processed SQL query.
boolean	supportsLimit()	Does this handler support some form of limiting query results via a SQL clause?
boolean	supportsLimitOffset()	Does this handler's LIMIT support (if any) additionally support specifying an offset?
boolean	supportsVariableLimit()	Does this handler support bind variables (i.e., prepared statement parameters) for its limit/offset?
boolean	useMaxForLimit()	Does the LIMIT clause take a "maximum" row number instead of a total number of returned rows?

从类继承的方法 org.hibernate.dialect.pagination.AbstractLimitHandler

bindLimitParameters, bindLimitParametersAtEndOfQuery, bindLimitParametersAtStartOfQuery, getMaxOrLimit, setMaxRows

从类继承的方法 java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

构造器详细资料

LegacyLimitHandler

public LegacyLimitHandler(Dialect dialect)

Constructs a LegacyLimitHandler

参数:

dialect - The dialect

方法详细资料

supportsLimit

public boolean supportsLimit()

从接口复制的说明: LimitHandler

Does this handler support some form of limiting query results via a SQL clause?

指定者:

supportsLimit 在接口中 LimitHandler

覆盖:

supportsLimit 在类中 AbstractLimitHandler

返回:

True if this handler supports some form of LIMIT.

supportsLimitOffset

public boolean supportsLimitOffset()

从接口复制的说明: LimitHandler

Does this handler's LIMIT support (if any) additionally support specifying an offset?

指定者:

supportsLimitOffset 在接口中 LimitHandler

覆盖:

supportsLimitOffset 在类中 AbstractLimitHandler

返回:

True if the handler supports an offset within the limit support.

supportsVariableLimit

public boolean supportsVariableLimit()

从类复制的说明: AbstractLimitHandler

Does this handler support bind variables (i.e., prepared statement parameters) for its limit/offset?

覆盖:

supportsVariableLimit 在类中 AbstractLimitHandler

返回:

True if bind variables can be used; false otherwise.

bindLimitParametersInReverseOrder

public boolean bindLimitParametersInReverseOrder()

从类复制的说明: AbstractLimitHandler

ANSI SQL defines the LIMIT clause to be in the form LIMIT offset, limit. Does this dialect require us to bind the parameters in reverse order?

覆盖:

bindLimitParametersInReverseOrder 在类中 AbstractLimitHandler

返回:

true if the correct order is limit, offset

bindLimitParametersFirst

public boolean bindLimitParametersFirst()

从类复制的说明: AbstractLimitHandler

Does the LIMIT clause come at the start of the SELECT statement, rather than at the end?

覆盖:

bindLimitParametersFirst 在类中 AbstractLimitHandler

返回:

true if limit parameters should come before other parameters

useMaxForLimit

public boolean useMaxForLimit()

从类复制的说明: AbstractLimitHandler

Does the LIMIT clause take a "maximum" row number instead of a total number of returned rows?

This is easiest understood via an example. Consider you have a table with 20 rows, but you only want to retrieve rows number 11 through 20. Generally, a limit with offset would say that the offset = 11 and the limit = 10 (we only want 10 rows at a time); this is specifying the total number of returned rows. Some dialects require that we instead specify offset = 11 and limit = 20, where 20 is the "last" row we want relative to offset (i.e. total number of rows = 20 - 11 = 9)

So essentially, is limit relative from offset? Or is limit absolute?

覆盖:

useMaxForLimit 在类中 AbstractLimitHandler

返回:

True if limit is relative from offset; false otherwise.

forceLimitUsage

public boolean forceLimitUsage()

从类复制的说明: AbstractLimitHandler

Generally, if there is no limit applied to a Hibernate query we do not apply any limits to the SQL query. This option forces that the limit be written to the SQL query.

覆盖:

forceLimitUsage 在类中 AbstractLimitHandler

返回:

True to force limit into SQL query even if none specified in Hibernate query; false otherwise.

convertToFirstRowValue

public int convertToFirstRowValue(int zeroBasedFirstResult)

从类复制的说明: AbstractLimitHandler

Hibernate APIs explicitly state that setFirstResult() should be a zero-based offset. Here we allow the Dialect a chance to convert that value based on what the underlying db or driver will expect.

NOTE: what gets passed into AbstractLimitHandler.processSql(String, org.hibernate.engine.spi.RowSelection) is the zero-based offset. Dialects which do not AbstractLimitHandler.supportsVariableLimit() should take care to perform any needed first-row-conversion calls prior to injecting the limit values into the SQL string.

覆盖:

convertToFirstRowValue 在类中 AbstractLimitHandler

参数:

zeroBasedFirstResult - The user-supplied, zero-based first row offset.

返回:

The corresponding db/dialect specific offset.

另请参阅:

Query.setFirstResult(int), Criteria.setFirstResult(int)

processSql

public String processSql(String sql,
                         RowSelection selection)

从接口复制的说明: LimitHandler

Return processed SQL query.

指定者:

processSql 在接口中 LimitHandler

覆盖:

processSql 在类中 AbstractLimitHandler

参数:

sql - the SQL query to process.

selection - the selection criteria for rows.

返回:

Query statement with LIMIT clause applied.