public class SQLServer2012LimitHandler extends SQLServer2005LimitHandler
LIMIT clause handler compatible with SQL Server 2012 and later.
Constructor and Description |
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SQLServer2012LimitHandler() |
Modifier and Type | Method and Description |
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int |
bindLimitParametersAtEndOfQuery(RowSelection selection,
PreparedStatement statement,
int index)
Bind parameter values needed by the LIMIT clause after original SELECT statement.
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int |
convertToFirstRowValue(int zeroBasedFirstResult)
Hibernate APIs explicitly state that setFirstResult() should be a zero-based offset.
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String |
processSql(String sql,
RowSelection selection)
Add a LIMIT clause to the given SQL SELECT (HHH-2655: ROW_NUMBER for Paging)
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boolean |
supportsLimit()
Does this handler support some form of limiting query results
via a SQL clause?
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boolean |
supportsVariableLimit()
Does this handler support bind variables (i.e., prepared statement
parameters) for its limit/offset?
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boolean |
useMaxForLimit()
Does the <tt>LIMIT</tt> clause take a "maximum" row number instead
of a total number of returned rows?
<p/>
This is easiest understood via an example.
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addTopExpression, bindLimitParametersAtStartOfQuery, encloseWithOuterQuery, fillAliasInSelectClause, supportsLimitOffset
bindLimitParameters, bindLimitParametersFirst, bindLimitParametersInReverseOrder, forceLimitUsage, getMaxOrLimit, setMaxRows
public boolean supportsLimit()
LimitHandler
Does this handler support some form of limiting query results via a SQL clause?
supportsLimit
in interface LimitHandler
supportsLimit
in class SQLServer2005LimitHandler
public boolean supportsVariableLimit()
AbstractLimitHandler
Does this handler support bind variables (i.e., prepared statement parameters) for its limit/offset?
supportsVariableLimit
in class SQLServer2005LimitHandler
public String processSql(String sql, RowSelection selection)
SQLServer2005LimitHandler
Add a LIMIT clause to the given SQL SELECT (HHH-2655: ROW_NUMBER for Paging)
The LIMIT SQL will look like:
<pre> WITH query AS ( SELECT inner_query.* , ROW_NUMBER() OVER (ORDER BY CURRENT_TIMESTAMP) as hibernate_row_nr FROM ( original_query_with_top_if_order_by_present_and_all_aliased_columns ) inner_query ) SELECT alias_list FROM query WHERE hibernate_row_nr >= offset AND hibernate_row_nr < offset + last </pre>
When offset equals 0, only <code>TOP(?)</code> expression is added to the original query.
processSql
in interface LimitHandler
processSql
in class SQLServer2005LimitHandler
sql
- the SQL query to process.selection
- the selection criteria for rows.public boolean useMaxForLimit()
AbstractLimitHandler
Does the <tt>LIMIT</tt> clause take a "maximum" row number instead of a total number of returned rows? <p/> 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) <p/> So essentially, is limit relative from offset? Or is limit absolute?
useMaxForLimit
in class SQLServer2005LimitHandler
public int convertToFirstRowValue(int zeroBasedFirstResult)
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.
<p/>
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.
convertToFirstRowValue
in class SQLServer2005LimitHandler
zeroBasedFirstResult
- The user-supplied, zero-based first row offset.Query.setFirstResult(int)
,
Criteria.setFirstResult(int)
public int bindLimitParametersAtEndOfQuery(RowSelection selection, PreparedStatement statement, int index) throws SQLException
LimitHandler
Bind parameter values needed by the LIMIT clause after original SELECT statement.
bindLimitParametersAtEndOfQuery
in interface LimitHandler
bindLimitParametersAtEndOfQuery
in class SQLServer2005LimitHandler
selection
- the selection criteria for rows.statement
- Statement to which to bind limit parameter values.index
- Index from which to start binding.SQLException
- Indicates problems binding parameter values.Copyright © 2001-2018 Red Hat, Inc. All Rights Reserved.