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/*
* Copyright (C) 2013 Tobias Brunner
* Copyright (C) 2008 Martin Willi
* Hochschule fuer Technik Rapperswil
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*/
/**
* @defgroup databasei database
* @{ @ingroup database
*/
#ifndef DATABASE_H_
#define DATABASE_H_
typedef enum db_type_t db_type_t;
typedef enum db_driver_t db_driver_t;
typedef struct database_t database_t;
#include <collections/enumerator.h>
/**
* Database column types
*/
enum db_type_t {
/** integer type, argument is an "int" */
DB_INT,
/** unsigned integer, argument is an "u_int" */
DB_UINT,
/** string type, argument is a "char*" */
DB_TEXT,
/** binary large object type, argument is a "chunk_t" */
DB_BLOB,
/** floating point, argument is a "double" */
DB_DOUBLE,
/** NULL, takes no argument */
DB_NULL,
};
/**
* Database implementation type.
*/
enum db_driver_t {
/** matches to other databases */
DB_ANY = 0,
/** SQLite database */
DB_SQLITE,
/** MySQL database */
DB_MYSQL,
};
/**
* Names for db_driver_t
*/
extern enum_name_t *db_driver_names;
/**
* Interface for a database implementation.
*
* @code
int affected, rowid, aint;
char *atext;
database_t *db;
enumerator_t *enumerator;
db = lib->database->create("mysql://user:pass@host/database");
affected = db->execute(db, &rowid, "INSERT INTO table VALUES (?, ?)",
DB_INT, 77, DB_TEXT, "a text");
printf("inserted %d row, new row ID: %d\n", affected, rowid);
enumerator = db->query(db, "SELECT aint, atext FROM table WHERE aint > ?",
DB_INT, 10, // 1 argument to SQL string
DB_INT, DB_TEXT); // 2 enumerated types in query
if (enumerator)
{
while (enumerator->enumerate(enumerator, &aint, &atext))
{
printf("%d: %s\n", aint, atext);
}
enumerator->destroy(enumerator);
}
@endcode
*/
struct database_t {
/**
* Run a query which returns rows, such as a SELECT.
*
* @param sql sql query string, containing '?' placeholders
* @param ... list of sql placeholder db_type_t followed by its value,
* followed by enumerators arguments as db_type_t's
* @return enumerator as defined with arguments, NULL on failure
*/
enumerator_t* (*query)(database_t *this, char *sql, ...);
/**
* Execute a query which does not return rows, such as INSERT.
*
* @param rowid pointer to write inserted AUTO_INCREMENT row ID, or NULL
* @param sql sql string, containing '?' placeholders
* @param ... list of sql placeholder db_type_t followed by its value
* @return number of affected rows, < 0 on failure
*/
int (*execute)(database_t *this, int *rowid, char *sql, ...);
/**
* Start a transaction.
*
* A serializable transaction forces a strict separation between other
* transactions. Due to the performance overhead they should only be used
* in certain situations (e.g. SELECT->INSERT|UPDATE).
*
* @note Either commit() or rollback() has to be called to end the
* transaction.
* @note Transactions are thread-specific. So commit()/rollbak() has to be
* called from the same thread.
* @note While this method can be called multiple times (commit/rollback
* have to be called an equal number of times) real nested transactions are
* not supported. So if any if the "inner" transactions are rolled back
* the outer most transaction is rolled back.
*
* @param serializable TRUE to create a serializable transaction
* @return TRUE on success
*/
bool (*transaction)(database_t *this, bool serializable);
/**
* Commit all changes made during the current transaction.
*
* @return TRUE on success
*/
bool (*commit)(database_t *this);
/**
* Rollback/revert all changes made during the current transaction.
*
* @return TRUE on success
*/
bool (*rollback)(database_t *this);
/**
* Get the database implementation type.
*
* To allow driver specific SQL or performance optimizations each database
* implementations can be queried for its type.
*
* @return database implementation type
*/
db_driver_t (*get_driver)(database_t *this);
/**
* Destroy a database connection.
*/
void (*destroy)(database_t *this);
};
#endif /** DATABASE_H_ @}*/
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