Add support for OPENXML with WITH clause

[harshdubey166]

Description

OPENXML provides a rowset view over an XML document. Since OPENXML is a rowset provider and it returns a set of rows, we can use OPENXML in the FROM clause of a T-SQL statement just as we can use any other table, view, or table-valued function. The WITH clause in OPENXML provides a rowset format (and additional mapping information as required) by using either SchemaDeclaration or specifying an existing TableName.
Currently Babelfish does not have support for openxml. So the primary objective is to add support for OPENXML with WITH clause.
The syntax of openxml is as follows :

OPENXML ( idoc int [ in ] , rowpattern nvarchar [ in ], [ flags byte [ in ] ] )
    [ WITH ( SchemaDeclaration | TableName ) ]

Arguments

• idoc
  • The document handle of the internal representation of an XML document. The internal representation of an XML document is created by calling sp_xml_preparedocument.
• rowpattern
  • The XPath pattern used to identify the nodes to be processed as rows. The nodes come from the XML document whose handle is passed in the idoc parameter.
• flags
  • Indicates the mapping used between the XML data and the relational rowset, and how the spill-over column is filled. flags is an optional input parameter, and can be one of the following values.

The WITH clause provides a rowset format (and additional mapping information as required) by using either SchemaDeclaration or specifying an existing TableName. If the optional WITH clause isn't specified, the results are returned in an edge table format. Edge tables represent the fine-grained XML document structure (such as element/attribute names, the document hierarchy, the namespaces, PIs, and so on) in a single table.

Engine PR : babelfish-for-postgresql/postgresql_modified_for_babelfish#587
Signed-off-by: Harsh Dubey [email protected]
Authored-by: Harsh Dubey [email protected]

Issues Resolved

BABEL-3635, BABEL-6045

Check List

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[coveralls]

Pull Request Test Coverage Report for Build 17972673400

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This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

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Details

• 110 of 122 (90.16%) changed or added relevant lines in 5 files are covered.
• 214 unchanged lines in 3 files lost coverage.
• Overall coverage increased (+0.03%) to 76.632%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
contrib/babelfishpg_tsql/src/procedures.c	29	33	87.88%
contrib/babelfishpg_tsql/src/hooks.c	73	81	90.12%

Files with Coverage Reduction	New Missed Lines	%
contrib/babelfishpg_tsql/src/pltsql_utils.c	1	92.28%
contrib/babelfishpg_tsql/src/guc.c	5	97.08%
contrib/babelfishpg_tsql/src/hooks.c	208	86.07%

Totals
Change from base Build 17918846922:	0.03%
Covered Lines:	51664
Relevant Lines:	67418

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💛 - Coveralls