Db Class Reference

The Db class provides a basic API for accessing the database programatically. It is used to set up the initial connection and various basic queries can be executed using a set of static functions. When interfacing with the database for the purpose of adding, deleting or updating entries, the use of the entry class and its subclasses is recommended. This clas is not supposed to be instantiated, if you need a database object, use QSqlDatabase::database("qt_sql_default_connection");. More...

#include <db.h>

Public Types
enum	editRole { createNew, editExisting }
	The editRole enum {createNew, editExisting} is used to differentiate between creating a new entry in the database vs editing an existing one.
enum	matchType { exactMatch, partialMatch }
	The matchType enum {exactMatch, partialMatch} is used to determine the matching when using a WHERE sql statement. exactMatch results in a "=" operator, whereas partiasMatch results in a "LIKE" operator.

Public Member Functions
	Db (Db const &)=delete
void	operator= (Db const &)=delete

Static Public Member Functions
static Db &	get ()
static void	connect ()
	connect establishes the database connection. Only needs to be called once within the application. Database is available thereafter, objects can be instantiated with QSqlDatabase::database("qt_sql_default_connection") as required.
static void	disconnect ()
	disconnect Closes and removes the default database connection.
static QSqlDatabase	Database ()
	Can be used to access the database connection. More...
static bool	exists (QString column, QString table, QString checkColumn, QString value, Db::matchType match)
	Db::exists checks if a certain value exists in the database with a sqlite WHERE statement. More...
static bool	singleUpdate (QString table, QString column, QString value, QString checkColumn, QString checkvalue, Db::matchType match)
	Db::singleUpdate Updates a single value in the database. Query format: UPDATE table SET column = value WHERE checkcolumn =/LIKE checkvalue. More...
static QString	singleSelect (QString column, QString table, QString checkColumn, QString value, Db::matchType match)
	singleSelect Returns a single value from the database with a sqlite WHERE statement More...
static QVector< QString >	multiSelect (QVector< QString > columns, QString table, QString checkColumn, QString value, Db::matchType match)
	Db::multiSelect Returns multiple values from the database with a sqlite WHERE statement. More...
static QVector< QString >	multiSelect (QVector< QString > columns, QString table)
	Db::multiSelect Returns a complete column(s) for a given table. More...
static QVector< QString >	customQuery (QString query, int returnValues)
	Db::customQuery Can be used to send a complex query to the database. More...

Detailed Description

The Db class provides a basic API for accessing the database programatically. It is used to set up the initial connection and various basic queries can be executed using a set of static functions. When interfacing with the database for the purpose of adding, deleting or updating entries, the use of the entry class and its subclasses is recommended. This clas is not supposed to be instantiated, if you need a database object, use QSqlDatabase::database("qt_sql_default_connection");.

Member Function Documentation

customQuery()

static QVector<QString> Db::customQuery ( QString  query, int  returnValues  )

inlinestatic

Db::customQuery Can be used to send a complex query to the database.

Parameters

query	- the full sql query statement
returnValues	- the number of expected return values

Returns

QVector<QString> of results

Database()

static QSqlDatabase Db::Database ( )

inlinestatic

Can be used to access the database connection.

Returns

a pointer to the default database connection

exists()

static bool Db::exists ( QString  column, QString  table, QString  checkColumn, QString  value, Db::matchType  match  )

inlinestatic

Db::exists checks if a certain value exists in the database with a sqlite WHERE statement.

Parameters

table	- Name of the table
column	- Name of the column
value	- The value to be checked

Returns

multiSelect() [1/2]

static QVector<QString> Db::multiSelect ( QVector< QString >  columns, QString  table  )

inlinestatic

Db::multiSelect Returns a complete column(s) for a given table.

Parameters

column	- QVector<QString> Names of the columns to be queried
table	- QString Name of the table

Returns

multiSelect() [2/2]

static QVector<QString> Db::multiSelect ( QVector< QString >  columns, QString  table, QString  checkColumn, QString  value, Db::matchType  match  )

inlinestatic

Db::multiSelect Returns multiple values from the database with a sqlite WHERE statement.

Parameters

table	- Name of the table
columns	- QVector<QString> Names of the columns to be queried
value	- Identifier for WHERE statement
checkColumn	- column to match value to
match	- enum Db::exactMatch or Db::partialMatch

Returns

QVector<QString>

singleSelect()

static QString Db::singleSelect ( QString  column, QString  table, QString  checkColumn, QString  value, Db::matchType  match  )

inlinestatic

singleSelect Returns a single value from the database with a sqlite WHERE statement

Parameters

table	- Name of the table
column	- Name of the column
value	- Identifier for WHERE statement
match	- enum Db::exactMatch or Db::partialMatch

Returns

QString

singleUpdate()

static bool Db::singleUpdate ( QString  table, QString  column, QString  value, QString  checkColumn, QString  checkvalue, Db::matchType  match  )

inlinestatic

Db::singleUpdate Updates a single value in the database. Query format: UPDATE table SET column = value WHERE checkcolumn =/LIKE checkvalue.

Parameters

table	Name of the table to be updated
column	Name of the column to be updated
checkColumn	Name of the column for WHERE statement
value	The value to be set
checkvalue	The value for the WHERE statement
match	enum Db::exactMatch or Db::partialMatch

Returns

true on success, otherwise error messages in debug out

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

• src/database/db.h
• src/database/db.cpp