aGrUM  0.13.2
gum::learning::DBInitializerFromSQL< ALLOC > Class Template Reference

The class for initializing DatabaseTable and RawDatabaseTable instances from SQL databases. More...

#include <agrum/learning/database/DBInitializerFromSQL.h>

+ Inheritance diagram for gum::learning::DBInitializerFromSQL< ALLOC >:
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Public Member Functions

Constructors / Destructors
 DBInitializerFromSQL (const std::string &dataSource, const std::string &login, const std::string &password, const std::string &query, long timeout=0L, const allocator_type &alloc=allocator_type())
 default constructor, especially for postgresql databases More...
 
 DBInitializerFromSQL (const std::string &connection_string, const std::string &query, long timeout=0L, const allocator_type &alloc=allocator_type())
 default constructor, especially for sqlite databases More...
 
 DBInitializerFromSQL (const DBInitializerFromSQL< ALLOC > &from)
 copy constructor More...
 
 DBInitializerFromSQL (const DBInitializerFromSQL< ALLOC > &from, const allocator_type &alloc)
 copy constructor with a given allocator More...
 
 DBInitializerFromSQL (DBInitializerFromSQL< ALLOC > &&from)
 move constructor More...
 
 DBInitializerFromSQL (DBInitializerFromSQL< ALLOC > &&from, const allocator_type &alloc)
 move constructor with a given allocator More...
 
virtual DBInitializerFromSQL< ALLOC > * clone () const
 virtual copy constructor More...
 
virtual DBInitializerFromSQL< ALLOC > * clone (const allocator_type &alloc) const
 virtual copy constructor with a given allocator More...
 
virtual ~DBInitializerFromSQL ()
 destructor More...
 
Operators
DBInitializerFromSQL< ALLOC > & operator= (const DBInitializerFromSQL< ALLOC > &from)
 copy operator More...
 
DBInitializerFromSQL< ALLOC > & operator= (DBInitializerFromSQL< ALLOC > &&from)
 move operator More...
 
Accessors / Modifiers
const std::vector< std::string, ALLOC< std::string > > & variableNames ()
 returns the names of the variables in the input dataset More...
 
template<template< template< typename > class > class DATABASE>
void fillDatabase (DATABASE< ALLOC > &database, const bool retry_insertion=false)
 fills the rows of the database table More...
 
std::size_t throwingColumn () const
 This method indicates which column filling raised an exception, if any, during the execution of fillDatabase. More...
 
allocator_type getAllocator () const
 returns the allocator used More...
 

Public Types

using allocator_type = ALLOC< std::string >
 type for the allocators passed in arguments of methods More...
 
enum  InputType : char { InputType::STRING, InputType::DBCELL }
 the enumeration indicating the type of the data the IDBInitializer expects as input data More...
 

Protected Member Functions

virtual std::vector< std::string, ALLOC< std::string > > _variableNames () final
 returns the names of the variables More...
 
virtual const std::vector< std::string, ALLOC< std::string > > & _currentStringRow () final
 returns the content of the current row using strings More...
 
virtual bool _nextRow () final
 indicates whether there is a next row to read (and point on it) More...
 
virtual const DBRow< DBCell, ALLOC > & _currentDBCellRow ()
 asks the child class for the content of the current row using dbcells More...
 

Detailed Description

template<template< typename > class ALLOC = std::allocator>
class gum::learning::DBInitializerFromSQL< ALLOC >

The class for initializing DatabaseTable and RawDatabaseTable instances from SQL databases.

In aGrUM, the usual way to create DatabaseTable instances used by learning algorithms is to use the 4-step process below:

  1. Create an IDBInitializer instance (either a DBInitializerFromCSV or a DBInitializerFromSQL). This will enable to get the variables corresponding to the columns of the DatabaseTable.
  2. Knowing these variables, create a DBTranslatorSet for encoding the lines of the CSV file or those of the SQL result into the appropriate values for the learning algorithms.
  3. Create the DatabaseTable, passing it the DBTranslatorSet created in the preceding step. Use the IDBInitializer to provide the variables' names to the DatabaseTable.
  4. Use the IDBInitializer to add the lines of the CSV file or those of the SQL result into the DatabaseTable.
The following codes show the details of this processe:
// 1/ use the initializer to parse all the columns/rows of a SQL result:
const std::string dataSource = "PostgreSQL";
const std::string login = "gonzales";
const std::string password = "agrum";
const std::string query = "SELECT * FROM testunit.asia";
initializer ( dataSource, login, password, query );
const auto& var_names = initializer.variableNames ();
const std::size_t nb_vars = var_names.size ();
// we create as many translators as there are variables
for ( std::size_t i = 0; i < nb_vars; ++i )
translator_set.insertTranslator ( translator, i );
// create a DatabaseTable with these translators. For the moment, the
// DatabaseTable will be empty, i.e., it will contain no row
gum::learning::DatabaseTable<> database ( translator_set );
database.setVariableNames( initializer.variableNames () );
// use the DBInitializerFromSQL to fill the rows:
initializer.fillDatabase ( database );
// now, the database contains all the content of the ASIA database
// 2/ use an IDBInitializer to initialize a DatabaseTable, but ignore
// some columns.
initializer2 ( dataSource, login, password, query );
gum::learning::DatabaseTable<> database2; // empty database
// indicate which columns of the SQL result should be read
database2.insertTranslator ( translator, 1 );
database2.insertTranslator ( translator, 3 );
database2.insertTranslator ( translator, 4 );
// sets the names of the columns correctly
database2.setVariableNames( initializer2.variableNames () );
// fill the rows:
initializer2.fillDatabase ( database2 );
// now all the rows of the SQL result have been transferred into
// database2, but only columns 1, 3 and 4 of the SQL result have
// been kept.
// 3/ another possibility to initialize a DatabaseTable, ignoring
// some columns:
initializer3 ( dataSource, login, password, query );
gum::learning::DatabaseTable<> database3 ( translator_set );
// here, database3 is an empty database but it contains already
// translators for all the columns of the SQL result. We shall now
// remove the columns/translators that are not wanted anymore
database3.ignoreColumn ( 0 );
database3.ignoreColumn ( 2 );
database3.ignoreColumn ( 5 );
database3.ignoreColumn ( 6 );
database3.ignoreColumn ( 7 );
// asia contains 8 columns. The above ignoreColumns keep only columns
// 1, 3 and 4.
// sets the names of the columns correctly
database3.setVariableNames( initializer3.variableNames () );
// fill the rows:
initializer3.fillDatabase ( database3 );
// now all the rows of the SQL result have been transferred into
// database3, but only columns 1, 3 and 4 of the SQL result have
// been kept.

Definition at line 134 of file DBInitializerFromSQL.h.

Member Typedef Documentation

template<template< typename > class ALLOC = std::allocator>
using gum::learning::DBInitializerFromSQL< ALLOC >::allocator_type = ALLOC< std::string >

type for the allocators passed in arguments of methods

Definition at line 137 of file DBInitializerFromSQL.h.

Member Enumeration Documentation

template<template< typename > class ALLOC>
enum gum::learning::IDBInitializer::InputType : char
stronginherited

the enumeration indicating the type of the data the IDBInitializer expects as input data

Enumerator
STRING 
DBCELL 

Definition at line 118 of file IDBInitializer.h.

118 : char { STRING, DBCELL };

Constructor & Destructor Documentation

template<template< typename > class ALLOC = std::allocator>
gum::learning::DBInitializerFromSQL< ALLOC >::DBInitializerFromSQL ( const std::string &  dataSource,
const std::string &  login,
const std::string &  password,
const std::string &  query,
long  timeout = 0L,
const allocator_type alloc = allocator_type() 
)

default constructor, especially for postgresql databases

This will read the result of query and load it in memory.

Parameters
dataSourceA declared dataSource in your odbc configuration file (usually /etc/odbc.ini).
loginThe dataSource login.
passwordThe dataSource password.
queryThe SQL query used as a database.
timeoutDefines a timeout for accessing the SQL database, if 0 then no timeout is set.
allocthe allocator used to allocate all the data structures
template<template< typename > class ALLOC = std::allocator>
gum::learning::DBInitializerFromSQL< ALLOC >::DBInitializerFromSQL ( const std::string &  connection_string,
const std::string &  query,
long  timeout = 0L,
const allocator_type alloc = allocator_type() 
)

default constructor, especially for sqlite databases

This will read the result of query and load it in memory.

Parameters
connection_stringa string specifying to nanODBC how to connect to a SQL database
queryThe SQL query used as a database.
timeoutDefines a timeout for accessing the SQL database, if 0 then no timeout is set.
allocthe allocator used to allocate all the data structures
template<template< typename > class ALLOC = std::allocator>
gum::learning::DBInitializerFromSQL< ALLOC >::DBInitializerFromSQL ( const DBInitializerFromSQL< ALLOC > &  from)

copy constructor

the new initializer points to the same SQL query as from, but it reparses the result it from scratch.

template<template< typename > class ALLOC = std::allocator>
gum::learning::DBInitializerFromSQL< ALLOC >::DBInitializerFromSQL ( const DBInitializerFromSQL< ALLOC > &  from,
const allocator_type alloc 
)

copy constructor with a given allocator

the new initializer points to the same SQL query as from, but it reparses the result from scratch.

template<template< typename > class ALLOC = std::allocator>
gum::learning::DBInitializerFromSQL< ALLOC >::DBInitializerFromSQL ( DBInitializerFromSQL< ALLOC > &&  from)

move constructor

template<template< typename > class ALLOC = std::allocator>
gum::learning::DBInitializerFromSQL< ALLOC >::DBInitializerFromSQL ( DBInitializerFromSQL< ALLOC > &&  from,
const allocator_type alloc 
)

move constructor with a given allocator

template<template< typename > class ALLOC = std::allocator>
virtual gum::learning::DBInitializerFromSQL< ALLOC >::~DBInitializerFromSQL ( )
virtual

destructor

Member Function Documentation

template<template< typename > class ALLOC>
virtual const DBRow< DBCell, ALLOC >& gum::learning::IDBInitializer< ALLOC >::_currentDBCellRow ( )
protectedvirtualinherited

asks the child class for the content of the current row using dbcells

If the child class parses DBRows, this method should be overloaded

template<template< typename > class ALLOC = std::allocator>
virtual const std::vector< std::string, ALLOC< std::string > >& gum::learning::DBInitializerFromSQL< ALLOC >::_currentStringRow ( )
finalprotectedvirtual

returns the content of the current row using strings

Reimplemented from gum::learning::IDBInitializer< ALLOC >.

template<template< typename > class ALLOC = std::allocator>
virtual bool gum::learning::DBInitializerFromSQL< ALLOC >::_nextRow ( )
finalprotectedvirtual

indicates whether there is a next row to read (and point on it)

Implements gum::learning::IDBInitializer< ALLOC >.

template<template< typename > class ALLOC = std::allocator>
virtual std::vector< std::string, ALLOC< std::string > > gum::learning::DBInitializerFromSQL< ALLOC >::_variableNames ( )
finalprotectedvirtual

returns the names of the variables

Implements gum::learning::IDBInitializer< ALLOC >.

template<template< typename > class ALLOC = std::allocator>
virtual DBInitializerFromSQL< ALLOC >* gum::learning::DBInitializerFromSQL< ALLOC >::clone ( ) const
virtual

virtual copy constructor

Implements gum::learning::IDBInitializer< ALLOC >.

template<template< typename > class ALLOC = std::allocator>
virtual DBInitializerFromSQL< ALLOC >* gum::learning::DBInitializerFromSQL< ALLOC >::clone ( const allocator_type alloc) const
virtual

virtual copy constructor with a given allocator

Implements gum::learning::IDBInitializer< ALLOC >.

template<template< typename > class ALLOC>
template<template< template< typename > class > class DATABASE>
void gum::learning::IDBInitializer< ALLOC >::fillDatabase ( DATABASE< ALLOC > &  database,
const bool  retry_insertion = false 
)
inherited

fills the rows of the database table

This method may raise exceptions when trying to insert new rows into the database table. See Method insertRow() of the database table.

Referenced by gum::learning::genericBNLearner::__readFile(), gum::learning::genericBNLearner::Database::Database(), and gum::learning::readFile().

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template<template< typename > class ALLOC>
allocator_type gum::learning::IDBInitializer< ALLOC >::getAllocator ( ) const
inherited

returns the allocator used

template<template< typename > class ALLOC = std::allocator>
DBInitializerFromSQL< ALLOC >& gum::learning::DBInitializerFromSQL< ALLOC >::operator= ( const DBInitializerFromSQL< ALLOC > &  from)

copy operator

the new initializer points to the same SQL query as from, but it reparses the result from scratch.

template<template< typename > class ALLOC = std::allocator>
DBInitializerFromSQL< ALLOC >& gum::learning::DBInitializerFromSQL< ALLOC >::operator= ( DBInitializerFromSQL< ALLOC > &&  from)

move operator

the new initializer points to the same SQL query as from, but it reparses the result from scratch.

template<template< typename > class ALLOC>
std::size_t gum::learning::IDBInitializer< ALLOC >::throwingColumn ( ) const
inherited

This method indicates which column filling raised an exception, if any, during the execution of fillDatabase.

template<template< typename > class ALLOC>
const std::vector< std::string, ALLOC< std::string > >& gum::learning::IDBInitializer< ALLOC >::variableNames ( )
inherited

returns the names of the variables in the input dataset

Referenced by gum::learning::genericBNLearner::__readFile(), gum::learning::genericBNLearner::Database::Database(), and gum::learning::readFile().

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