Package org.hibernate.dialect.pagination

Class SQLServer2005LimitHandler

    • Constructor Detail

      • SQLServer2005LimitHandler

        public SQLServer2005LimitHandler()
        Constructs a SQLServer2005LimitHandler

    • Method Detail

      • useMaxForLimit

        public boolean useMaxForLimit()
        Description copied from class: 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?

        Overrides:
        useMaxForLimit in class AbstractLimitHandler
        Returns:
        True if limit is relative from offset; false otherwise.

      • supportsVariableLimit

        public boolean supportsVariableLimit()
        Description copied from class: AbstractLimitHandler
        Does this handler support bind variables (i.e., prepared statement parameters) for its limit/offset?
        Overrides:
        supportsVariableLimit in class AbstractLimitHandler
        Returns:
        True if bind variables can be used; false otherwise.

      • processSql

        public String processSql​(String sql,
                         RowSelection selection)
        Add a LIMIT clause to the given SQL SELECT (HHH-2655: ROW_NUMBER for Paging) The LIMIT SQL will look like: 
         WITH query AS (
   SELECT inner_query.*
        , ROW_NUMBER() OVER (ORDER BY CURRENT_TIMESTAMP) as __row__
     FROM ( original_query_with_top_if_order_by_present_and_all_aliased_columns ) inner_query
 )
 SELECT alias_list FROM query WHERE __row__ >= offset AND __row__ < offset + last
        When offset equals 0, only TOP(?) expression is added to the original query.
        Specified by:
        processSql in interface LimitHandler
        Overrides:
        processSql in class AbstractLimitHandler
        Parameters:
        sql - the SQL query to process.
        selection - the selection criteria for rows.
        Returns:
        A new SQL statement with the LIMIT clause applied.

      • fillAliasInSelectClause

        protected String fillAliasInSelectClause​(StringBuilder sb,
                                         int offset)
        Adds missing aliases in provided SELECT clause and returns coma-separated list of them. If query takes advantage of expressions like * or {table}.* inside SELECT clause, method returns *.
        Parameters:
        sb - SQL query.
        offset - the starting offset.
        Returns:
        List of aliases separated with comas or *.

      • encloseWithOuterQuery

        protected void encloseWithOuterQuery​(StringBuilder sql,
                                     int offset)
        Encloses original SQL statement with outer query that provides __row__ column.
        Parameters:
        sql - SQL query.
        offset - SQL query offset.