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LcgInfo::SQLQueryTranslator Class Reference

This class (actually, extending ones, since this is not instantiable) is used to translate a query posed to a canonical relational schema into a new query that can be posed to an equivalent schema (i.e.: containing the same actual information), in order to retrieve the same information. More...

#include <SQLQueryTranslator.h>

Inheritance diagram for LcgInfo::SQLQueryTranslator:

List of all members.

Public Methods
	SQLQueryTranslator ()
	Constructor using "./mappingGlueRMA" as the default name for the mapfile. More...
	SQLQueryTranslator (std::string const &pMapFile)
	Constructor passing the name of the file that has to be used for the mapping. More...
	SQLQueryTranslator (LcgConfigBuffer::ConfigBuffer &pMap)
	Constructor passing a reference to the already existing LcgConfigBuffer::ConfigBuffer object that is used for the mapping. More...
virtual	~SQLQueryTranslator ()
	Destructor of the class.
virtual std::vector< std::string >	translateQuery (std::string const &pQueryCanonical)=0
	Translates the specified query (intended to be posed to the canonical schema) into some new queries that can be posed to the implementation specific schema (in order) to retrieve the same information. More...
void	translateSemantic (std::string const &pQueryCanonical, SQLPredicateTree &pPred, std::vector< std::string > &pRowsToReturn, std::set< std::string > &pNewTableList)
	Makes the semantic translation of the specified query (intended to be posed to the canonical schema). More...
Static Protected Attributes
std::string const	CHARS_TO_DIVIDE_SQL_WORDS = "\t ,"
std::string const	CHARS_POSSIBLY_ESCAPED = "%"

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Detailed Description

This class (actually, extending ones, since this is not instantiable) is used to translate a query posed to a canonical relational schema into a new query that can be posed to an equivalent schema (i.e.: containing the same actual information), in order to retrieve the same information.

The equivalent schema is mapped to the canonical one using a mapping file (whose syntax must conform to that defined in ...) The query language used to express the original query must be SQL and the one for the resulting query will be defined in classes extending this one. For instance a SQLtoLDAPQueryTranslator would implement the virtual methods here defined for the SQL query language as input an LDAP query language as output.

Author:

LCG's EIS Group. CERN.

Version:

1.0

Date:

2004.

Definition at line 32 of file SQLQueryTranslator.h.

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Constructor & Destructor Documentation

SQLQueryTranslator::SQLQueryTranslator (    )

Constructor using "./mappingGlueRMA" as the default name for the mapfile. It may throw a QueryTranslationException if the specified mapping file cannot be loaded. Please do not use this constructor. Definition at line 16 of file SQLQueryTranslator.cpp.

SQLQueryTranslator::SQLQueryTranslator (  std::string const &    pMapFile )

Constructor passing the name of the file that has to be used for the mapping. It may throw a QueryTranslationException if the specified mapping file cannot be loaded. Parameters: pMapFile  The name of the mapping file Definition at line 20 of file SQLQueryTranslator.cpp.

SQLQueryTranslator::SQLQueryTranslator (  LcgConfigBuffer::ConfigBuffer &    pMap )

Constructor passing a reference to the already existing LcgConfigBuffer::ConfigBuffer object that is used for the mapping. Using this constructor implies that the LcgConfigBuffer::ConfigBuffer object was instantiated externally, and it requires that it does not go out of scope. Parameters: pMap  A reference to the LcgConfigBuffer::ConfigBuffer object used for the mapping Definition at line 24 of file SQLQueryTranslator.cpp.

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Member Function Documentation

virtual std::vector<std::string> LcgInfo::SQLQueryTranslator::translateQuery (  std::string const &    pQueryCanonical )  [pure virtual]

Translates the specified query (intended to be posed to the canonical schema) into some new queries that can be posed to the implementation specific schema (in order) to retrieve the same information. Several queries may be needed for cases where the output language does not support joins. In that case, queries refer to the results of the other by "n#", where "n" is the query number. It may throw a QueryTranslationException if there are problems parsing the specified predicate Parameters: pQueryCanonical  the query to be translated Returns: the resulting translated queries Implements LcgInfo::QueryTranslator. Implemented in LcgInfo::SQLtoLDAPQueryTranslator.

void SQLQueryTranslator::translateSemantic (  std::string const &    pQueryCanonical, SQLPredicateTree &    pPred, std::vector< std::string > &    pRowsToReturn, std::set< std::string > &    pNewTableList )

Makes the semantic translation of the specified query (intended to be posed to the canonical schema). It alters some parameter variables, so that the translateQuery() method can complete the query translation (adding the syntactic one, if applicable). It may throw a QueryTranslationException if there are problems parsing the specified predicate See also: translateQuery Parameters: pQueryCanonical  the query to be translated pPred  reference to store the translated predicate tree pRowsToReturn  list of rows to be returned (SELECT part of the query) pNewTableList  list of tables to complete the talbe.row names (FROM part of the query) Definition at line 31 of file SQLQueryTranslator.cpp. References LcgInfo::escapeLiterals, LcgInfo::extractTable, LcgInfo::int2str, LcgInfo::QueryTranslator::mTRowT, LcgInfo::nocaseCompare, LcgInfo::tokenizeStrWithIndices, and LcgInfo::unescapeLiterals. Referenced by LcgInfo::SQLtoSQLQueryTranslator::translateQuery, and LcgInfo::SQLtoLDAPQueryTranslator::translateQuery.

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The documentation for this class was generated from the following files:

• SQLQueryTranslator.h
• SQLQueryTranslator.cpp

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