db_t Class Reference

#import <db_t.h>

Inheritance diagram for db_t:

List of all members.

Public Member Functions
(id)	init
(int)	init_2nd_stage
(id)	free
(int)	save_record_to_db::
(int)	fetch_record_from_db::
(int)	delete_record_in_db::
(int)	delete_subrecords_in_db::
(void)	find_largest_keys_for_record::
(void)	unlock_record_in_db:
(maybe_t)	lock_record_in_db:
(char *)	is_record_locked:
(long)	new_recid::
(maybe_t)	find_keys_for_record::
(int)	do_exec:
(void)	freeres
(void)	update_kort_ui:
(pointerlist_t *)	list_of_instances:::
(int)	find_last_saved_field:
(maybe_t)	find_allowed_value:::::
Static Public Member Functions
(id)	init_with_values:
Protected Attributes
appbus_t *	bus
MYSQL	mysli
char *	sql_statement
MYSQL_RES *	resultset_of_query
MYSQL_ROW	exactly_one_row
my_ulonglong	how_many_rows
char	lock_info_string [200]
char	lock_info_string_of_locked_record [200]

---

Detailed Description

here is class for db access.

---

Member Function Documentation

- (int) delete_record_in_db: (id< valuepair_p > *)  values : (id< record_status_p >)  recstat

removes record from db Parameters: values  is pointer to values of the record about to be deleted. and most likely this method does not even use this parameter for any purpose. recstat  is record status structure Returns: 0 in success, something else otherwise

- (int) delete_subrecords_in_db: (record_t *)  aRecord : (long)  record_id_master

removes sub-records from db Parameters: aRecord  is pointer to record_t record_id_master  is value of record_id_master surrogate of the records in db table that are in need of deletion. Returns: 0 in success, something else otherwise

- (int) do_exec: (expected_query_result_t)  aExpectedResult

method for executing a query, takes input from instance variable sql_statement. this is the workhorse that does all select/update/delete/etc. Parameters: aExpectedResult  tells do_exec how many rows we expect in return. If this method is told that one line is expected, then this method will also fetch the one row if the query turns out to be a successful one. Returns: error code, 0 on success

- (int) fetch_record_from_db: (id< valuepair_p > *)  values : (id< record_status_p >)  recstat

gets record to db Parameters: values  is list values for database record recstat  is record status structure Returns: 0 in success, something else otherwise

- (maybe_t) find_allowed_value: (id< record_status_p >)  aRecStat : (id< valuepair_p >)  aValue : (wchar_t *)  aCurrentValue : (char *)  aAllowedValuesTable : (char *)  aAllowedValuesColumn

method for finding out if current value is among allowed ones and if not, helping user in choosing one. note that user has no other possibility but to choose one :-) Parameters: aRecStat  is status of the record where aValue belongs to aValue  is the value (form field) whose value we're seeking aCurrentValue  is the value as wchar_t directly from field aAllowedValuesTable  is db table where list of allowed values is found aAllowedValuesColumn  is db column where list of allowed values is found Returns: returns yes when a full screen update is in order

- (maybe_t) find_keys_for_record: (id< valuepair_p > *)  values : (id< record_status_p >)  recstat

method that finds keys for a record. may require user interaction. Parameters: values  is list of values in current record recstat  is the record status interface Returns: yes on success

- (void) find_largest_keys_for_record: (id< valuepair_p > *)  values : (id< record_status_p >)  recstat

invents surrogate keys for a record not yet fetched Parameters: values  is list values for database record recstat  is record status structure Returns: none

- (int) find_last_saved_field: (id< valuepair_p > *)  values

method that finds index of last field from form that is saved to db. Parameters: values  is the set of values from form Returns: index or last saved value or -1 if there is none

- (id) free

frees allocated memory

- (void) freeres

method for releasing in safe manner memory allocated by query results

- (id) init

default initializer

- (int) init_2nd_stage

this method asks for password and creates db connection

+ (id) init_with_values: (appbus_t *)  aBus

the "allocator" usually used is here

- (char *) is_record_locked: (id< record_status_p >)  recstat

queries for lockedness of a record Parameters: recstat  is record status structure Returns: lock string if record is locked, NULL if not

- (pointerlist_t *) list_of_instances: (char *)  recname : (long)  recid : (long)  recid_master

method that returns list of network addresses of other instances of this program. format of the list may depend on underlying network protocol, in UDP case it might be something like host:port Parameters: recname  if non-NULL only ui:s registered to this record name will be included to list recid  if non- -01 only ui:s registered to this recid will be included in the list. This is evaluated only if recname is non-NULL. recid_master  same meaning as with recid but for recid_master. Returns: pointerlist_t that the caller will own and hopefully delete. in case of error nil may be returned

- (maybe_t) lock_record_in_db: (id< record_status_p >)  recstat

locks a record in db from others to use Parameters: recstat  is record status structure Returns: yes if locking did succeed.

- (long) new_recid: (id< valuepair_p > *)  values : (id< record_status_p >)  recstat

returns unique long for tab/col pair Parameters: values  is list values for database record recstat  is record status structure Returns: none

- (int) save_record_to_db: (id< valuepair_p > *)  values : (id< record_status_p >)  recstat

saves record to db Parameters: values  is list values for database record recstat  is record status structure Returns: 0 in success, something else otherwise

- (void) unlock_record_in_db: (id< record_status_p >)  recstat

unlocks a record in db for others to use Parameters: recstat  is record status structure Returns: none

- (void) update_kort_ui: (id< record_status_p >)  aRecStat

method for maintaining kort_ui table

---

Member Data Documentation

- (appbus_t*) bus [protected]

application bus pointer

- (MYSQL_ROW) exactly_one_row [protected]

one row from resultset of last query

- (my_ulonglong) how_many_rows [protected]

size of resultset of last query

- (char lock_info_string[200]) [protected]

our id string saved to kort_ui table

- (char lock_info_string_of_locked_record[200]) [protected]

our id string saved to some data table

- (MYSQL) mysli [protected]

actual database handle

- (MYSQL_RES*) resultset_of_query [protected]

resultset of last query

- (char*) sql_statement [protected]

pointer to sql statement text about to be executed

---

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

• db_t.h

---