1QSqlCursor(3qt) QSqlCursor(3qt)
2
6 QSqlCursor - Browsing and editing of SQL tables and views
7
9 #include <qsqlcursor.h>
10 Inherits QSqlRecord and QSqlQuery.
12 Inherited by QSqlSelectCursor.
14 Public Members
16 QSqlCursor ( const QString & name = QString::null, bool autopopulate =
17 TRUE, QSqlDatabase * db = 0 )
18 QSqlCursor ( const QSqlCursor & other )
19 QSqlCursor & operator= ( const QSqlCursor & other )
20 ~QSqlCursor ()
21 enum Mode { ReadOnly = 0, Insert = 1, Update = 2, Delete = 4, Writable
22 = 7 }
23 virtual QSqlIndex primaryIndex ( bool setFromCursor = TRUE ) const
24 virtual QSqlIndex index ( const QStringList & fieldNames ) const
25 QSqlIndex index ( const QString & fieldName ) const
26 QSqlIndex index ( const char * fieldName ) const
27 virtual void setPrimaryIndex ( const QSqlIndex & idx )
28 virtual void append ( const QSqlFieldInfo & fieldInfo )
29 virtual void insert ( int pos, const QSqlFieldInfo & fieldInfo )
30 virtual void remove ( int pos )
31 virtual void clear ()
32 virtual void setGenerated ( const QString & name, bool generated )
33 virtual void setGenerated ( int i, bool generated )
34 virtual QSqlRecord * editBuffer ( bool copy = FALSE )
35 virtual QSqlRecord * primeInsert ()
36 virtual QSqlRecord * primeUpdate ()
37 virtual QSqlRecord * primeDelete ()
38 virtual int insert ( bool invalidate = TRUE )
39 virtual int update ( bool invalidate = TRUE )
40 virtual int del ( bool invalidate = TRUE )
41 virtual void setMode ( int mode )
42 int mode () const
43 virtual void setCalculated ( const QString & name, bool calculated )
44 bool isCalculated ( const QString & name ) const
45 virtual void setTrimmed ( const QString & name, bool trim )
46 bool isTrimmed ( const QString & name ) const
47 bool isReadOnly () const
48 bool canInsert () const
49 bool canUpdate () const
50 bool canDelete () const
51 bool select ()
52 bool select ( const QSqlIndex & sort )
53 bool select ( const QSqlIndex & filter, const QSqlIndex & sort )
54 virtual bool select ( const QString & filter, const QSqlIndex & sort =
55 QSqlIndex ( ) )
56 virtual void setSort ( const QSqlIndex & sort )
57 QSqlIndex sort () const
58 virtual void setFilter ( const QString & filter )
59 QString filter () const
60 virtual void setName ( const QString & name, bool autopopulate = TRUE )
61 QString name () const
62 bool isNull ( int i ) const
63 bool isNull ( const QString & name ) const
64 Protected Members
66 virtual QVariant calculateField ( const QString & name )
67 virtual int update ( const QString & filter, bool invalidate = TRUE )
68 virtual int del ( const QString & filter, bool invalidate = TRUE )
69 virtual QString toString ( const QString & prefix, QSqlField * field,
70 const QString & fieldSep ) const
71 virtual QString toString ( QSqlRecord * rec, const QString & prefix,
72 const QString & fieldSep, const QString & sep ) const
73 virtual QString toString ( const QSqlIndex & i, QSqlRecord * rec, const
74 QString & prefix, const QString & fieldSep, const QString & sep )
75 const
76
78 The QSqlCursor class provides browsing and editing of SQL tables and
79 views.
80 A QSqlCursor is a database record (see QSqlRecord) that corresponds to
82 a table or view within an SQL database (see QSqlDatabase). There are
83 two buffers in a cursor, one used for browsing and one used for editing
84 records. Each buffer contains a list of fields which correspond to the
85 fields in the table or view.
86 When positioned on a valid record, the browse buffer contains the
88 values of the current record's fields from the database. The edit
89 buffer is separate, and is used for editing existing records and
90 inserting new records.
91 For browsing data, a cursor must first select() data from the database.
93 After a successful select() the cursor is active (isActive() returns
94 TRUE), but is initially not positioned on a valid record (isValid()
95 returns FALSE). To position the cursor on a valid record, use one of
96 the navigation functions, next(), prev(), first(), last(), or seek().
97 Once positioned on a valid record, data can be retrieved from the
98 browse buffer using value(). If a navigation function is not
99 successful, it returns FALSE, the cursor will no longer be positioned
100 on a valid record and the values returned by value() are undefined.
101 For example:
103 QSqlCursor cur( "staff" ); // Specify the table/view name
105 cur.select(); // We'll retrieve every record
106 while ( cur.next() ) {
107 qDebug( cur.value( "id" ).toString() + ": " +
108 cur.value( "surname" ).toString() + " " +
109 cur.value( "salary" ).toString() );
110 }
111 In the above example, a cursor is created specifying a table or view
113 name in the database. Then, select() is called, which can be optionally
114 parameterised to filter and order the records retrieved. Each record in
115 the cursor is retrieved using next(). When next() returns FALSE, there
116 are no more records to process, and the loop terminates.
117 For editing records (rows of data), a cursor contains a separate edit
119 buffer which is independent of the fields used when browsing. The
120 functions insert(), update() and del() operate on the edit buffer. This
121 allows the cursor to be repositioned to other records while
122 simultaneously maintaining a separate buffer for edits. You can get a
123 pointer to the edit buffer using editBuffer(). The primeInsert(),
124 primeUpdate() and primeDelete() functions also return a pointer to the
125 edit buffer and prepare it for insert, update and delete respectively.
126 Edit operations only affect a single row at a time. Note that update()
127 and del() require that the table or view contain a primaryIndex() to
128 ensure that edit operations affect a unique record within the database.
129 For example:
131 QSqlCursor cur( "prices" );
133 cur.select( "id=202" );
134 if ( cur.next() ) {
135 QSqlRecord *buffer = cur.primeUpdate();
136 double price = buffer->value( "price" ).toDouble();
137 double newprice = price * 1.05;
138 buffer->setValue( "price", newprice );
139 cur.update();
140 }
141 To edit an existing database record, first move to the record you wish
143 to update. Call primeUpdate() to get the pointer to the cursor's edit
144 buffer. Then use this pointer to modify the values in the edit buffer.
145 Finally, call update() to save the changes to the database. The values
146 in the edit buffer will be used to locate the appropriate record when
147 updating the database (see primaryIndex()).
148 Similarly, when deleting an existing database record, first move to the
150 record you wish to delete. Then, call primeDelete() to get the pointer
151 to the edit buffer. Finally, call del() to delete the record from the
152 database. Again, the values in the edit buffer will be used to locate
153 and delete the appropriate record.
154 To insert a new record, call primeInsert() to get the pointer to the
156 edit buffer. Use this pointer to populate the edit buffer with new
157 values and then insert() the record into the database.
158 After calling insert(), update() or del(), the cursor is no longer
160 positioned on a valid record and can no longer be navigated (isValid()
161 return FALSE). The reason for this is that any changes made to the
162 database will not be visible until select() is called to refresh the
163 cursor. You can change this behavior by passing FALSE to insert(),
164 update() or del() which will prevent the cursor from becoming invalid.
165 The edits will still not be visible when navigating the cursor until
166 select() is called.
167 QSqlCursor contains virtual methods which allow editing behavior to be
169 customized by subclasses. This allows custom cursors to be created that
170 encapsulate the editing behavior of a database table for an entire
171 application. For example, a cursor can be customized to always auto-
172 number primary index fields, or provide fields with suitable default
173 values, when inserting new records. QSqlCursor generates SQL statements
174 which are sent to the database engine; you can control which fields are
175 included in these statements using setGenerated().
176 Note that QSqlCursor does not inherit from QObject. This means that you
178 are responsible for destroying instances of this class yourself.
179 However if you create a QSqlCursor and use it in a QDataTable,
180 QDataBrowser or a QDataView these classes will usually take ownership
181 of the cursor and destroy it when they don't need it anymore. The
182 documentation for QDataTable, QDataBrowser and QDataView explicitly
183 states which calls take ownership of the cursor.
184 See also Database Classes.
186 Member Type Documentation
189 This enum type describes how QSqlCursor operates on records in the
190 database.
191 QSqlCursor::ReadOnly - the cursor can only SELECT records from the
193 database.
194 QSqlCursor::Insert - the cursor can INSERT records into the database.
196 QSqlCursor::Update - the cursor can UPDATE records in the database.
198 QSqlCursor::Delete - the cursor can DELETE records from the database.
200 QSqlCursor::Writable - the cursor can INSERT, UPDATE and DELETE records
202 in the database.
203
206 autopopulate = TRUE, QSqlDatabase * db = 0 )
207 Constructs a cursor on database db using table or view name.
208 If autopopulate is TRUE (the default), the name of the cursor must
210 correspond to an existing table or view name in the database so that
211 field information can be automatically created. If the table or view
212 does not exist, the cursor will not be functional.
213 The cursor is created with an initial mode of QSqlCursor::Writable
215 (meaning that records can be inserted, updated or deleted using the
216 cursor). If the cursor does not have a unique primary index, update and
217 deletes cannot be performed.
218 Note that autopopulate refers to populating the cursor with meta-data,
220 e.g. the names of the table's fields, not with retrieving data. The
221 select() function is used to populate the cursor with data.
222 See also setName() and setMode().
224
226 Constructs a copy of other.
227
229 Destroys the object and frees any allocated resources.
230
232 Append a copy of field fieldInfo to the end of the cursor. Note that
233 all references to the cursor edit buffer become invalidated.
234
236 protected]
237 Protected virtual function which is called whenever a field needs to be
238 calculated. If calculated fields are being used, derived classes must
239 reimplement this function and return the appropriate value for field
240 name. The default implementation returns an invalid QVariant.
241 See also setCalculated().
243 Examples:
245
247 Returns TRUE if the cursor will perform deletes; otherwise returns
248 FALSE.
249 See also setMode().
251
253 Returns TRUE if the cursor will perform inserts; otherwise returns
254 FALSE.
255 See also setMode().
257
259 Returns TRUE if the cursor will perform updates; otherwise returns
260 FALSE.
261 See also setMode().
263
265 Removes all fields from the cursor. Note that all references to the
266 cursor edit buffer become invalidated.
267 Reimplemented from QSqlRecord.
269
271 Deletes a record from the database using the cursor's primary index and
272 the contents of the cursor edit buffer. Returns the number of records
273 which were deleted. For error information, use lastError().
274 Only records which meet the filter criteria specified by the cursor's
276 primary index are deleted. If the cursor does not contain a primary
277 index, no delete is performed and 0 is returned. If invalidate is TRUE
278 (the default), the current cursor can no longer be navigated. A new
279 select() call must be made before you can move to a valid record. For
280 example:
281 QSqlCursor cur( "prices" );
283 cur.select( "id=999" );
284 if ( cur.next() ) {
285 cur.primeDelete();
286 cur.del();
287 }
288 In the above example, a cursor is created on the 'prices' table and
290 positioned to the record to be deleted. First primeDelete() is called
291 to populate the edit buffer with the current cursor values, e.g. with
292 an id of 999, and then del() is called to actually delete the record
293 from the database. Remember: all edit operations (insert(), update()
294 and delete()) operate on the contents of the cursor edit buffer and not
295 on the contents of the cursor itself.
296 See also primeDelete(), setMode(), and lastError().
298 Example: sql/overview/delete/main.cpp.
300
302 [virtual protected]
303 This is an overloaded member function, provided for convenience. It
304 behaves essentially like the above function.
305 Deletes the current cursor record from the database using the filter
307 filter. Only records which meet the filter criteria are deleted.
308 Returns the number of records which were deleted. If invalidate is TRUE
309 (the default), the current cursor can no longer be navigated. A new
310 select() call must be made before you can move to a valid record. For
311 error information, use lastError().
312 The filter is an SQL WHERE clause, e.g. id=500.
314 See also setMode() and lastError().
316
318 Returns the current internal edit buffer. If copy is TRUE (the default
319 is FALSE), the current cursor field values are first copied into the
320 edit buffer. The edit buffer is valid as long as the cursor remains
321 valid. The cursor retains ownership of the returned pointer, so it must
322 not be deleted or modified.
323 See also primeInsert(), primeUpdate(), and primeDelete().
325
327 Returns the current filter, or an empty string if there is no current
328 filter.
329
331 Returns an index composed of fieldNames, all in ASCending order. Note
333 that all field names must exist in the cursor, otherwise an empty index
334 is returned.
335 See also QSqlIndex.
337 Examples:
339
341 This is an overloaded member function, provided for convenience. It
342 behaves essentially like the above function.
343 Returns an index based on fieldName.
345
347 This is an overloaded member function, provided for convenience. It
348 behaves essentially like the above function.
349 Returns an index based on fieldName.
351
353 Insert a copy of fieldInfo at position pos. If a field already exists
355 at pos, it is removed. Note that all references to the cursor edit
356 buffer become invalidated.
357 Examples:
359
361 This is an overloaded member function, provided for convenience. It
362 behaves essentially like the above function.
363 Inserts the current contents of the cursor's edit record buffer into
365 the database, if the cursor allows inserts. Returns the number of rows
366 affected by the insert. For error information, use lastError().
367 If invalidate is TRUE (the default), the cursor will no longer be
369 positioned on a valid record and can no longer be navigated. A new
370 select() call must be made before navigating to a valid record.
371 QSqlCursor cur( "prices" );
373 QSqlRecord *buffer = cur.primeInsert();
374 buffer->setValue( "id", 53981 );
375 buffer->setValue( "name", "Thingy" );
376 buffer->setValue( "price", 105.75 );
377 cur.insert();
378 In the above example, a cursor is created on the 'prices' table and a
380 pointer to the insert buffer is aquired using primeInsert(). Each
381 field's value is set to the desired value and then insert() is called
382 to insert the data into the database. Remember: all edit operations
383 (insert(), update() and delete()) operate on the contents of the cursor
384 edit buffer and not on the contents of the cursor itself.
385 See also setMode() and lastError().
387
389 Returns TRUE if the field name exists and is calculated; otherwise
390 returns FALSE.
391 See also setCalculated().
393
395 Returns TRUE if the field i is NULL or if there is no field at position
396 i; otherwise returns FALSE.
397 This is the same as calling QSqlRecord::isNull( i )
399
401 This is an overloaded member function, provided for convenience. It
402 behaves essentially like the above function.
403 Returns TRUE if the field called name is NULL or if there is no field
405 called name; otherwise returns FALSE.
406 This is the same as calling QSqlRecord::isNull( name )
408
410 Returns TRUE if the cursor is read-only; otherwise returns FALSE. The
411 default is FALSE. Read-only cursors cannot be edited using insert(),
412 update() or del().
413 See also setMode().
415
417 Returns TRUE if the field name exists and is trimmed; otherwise returns
418 FALSE.
419 When a trimmed field of type string or cstring is read from the
421 database any trailing (right-most) spaces are removed.
422 See also setTrimmed().
424
426 Returns the current cursor mode.
427 See also setMode().
429
431 Returns the name of the cursor.
432
434 Sets the cursor equal to other.
435
437 [virtual]
438 Returns the primary index associated with the cursor as defined in the
439 database, or an empty index if there is no primary index. If
440 setFromCursor is TRUE (the default), the index fields are populated
441 with the corresponding values in the cursor's current record.
442
444 This function primes the edit buffer's field values for delete and
445 returns the edit buffer. The default implementation copies the field
446 values from the current cursor record into the edit buffer (therefore,
447 this function is equivalent to calling editBuffer( TRUE ) ). The cursor
448 retains ownership of the returned pointer, so it must not be deleted or
449 modified.
450 See also editBuffer() and del().
452 Example: sql/overview/delete/main.cpp.
454
456 This function primes the edit buffer's field values for insert and
457 returns the edit buffer. The default implementation clears all field
458 values in the edit buffer. The cursor retains ownership of the returned
459 pointer, so it must not be deleted or modified.
460 See also editBuffer() and insert().
462 Examples:
464
466 This function primes the edit buffer's field values for update and
467 returns the edit buffer. The default implementation copies the field
468 values from the current cursor record into the edit buffer (therefore,
469 this function is equivalent to calling editBuffer( TRUE ) ). The cursor
470 retains ownership of the returned pointer, so it must not be deleted or
471 modified.
472 See also editBuffer() and update().
474 Examples:
476
478 Removes the field at pos. If pos does not exist, nothing happens. Note
479 that all references to the cursor edit buffer become invalidated.
480 Reimplemented from QSqlRecord.
482
484 QSqlIndex ( ) ) [virtual]
485 Selects all fields in the cursor from the database matching the filter
486 criteria filter. The data is returned in the order specified by the
487 index sort. Returns TRUE if the data was successfully selected;
488 otherwise returns FALSE.
489 The filter is a string containing a SQL WHERE clause but without the
491 'WHERE' keyword. The cursor is initially positioned at an invalid row
492 after this function is called. To move to a valid row, use seek(),
493 first(), last(), prev() or next().
494 Example:
496 QSqlCursor cur( "Employee" ); // Use the Employee table or view
498 cur.select( "deptno=10" ); // select all records in department 10
499 while( cur.next() ) {
500 ... // process data
501 }
502 ...
503 // select records in other departments, ordered by department number
504 cur.select( "deptno>10", cur.index( "deptno" ) );
505 ...
506 The filter will apply to any subsequent select() calls that do not
508 explicitly specify another filter. Similarly the sort will apply to any
509 subsequent select() calls that do not explicitly specify another sort.
510 QSqlCursor cur( "Employee" );
512 cur.select( "deptno=10" ); // select all records in department 10
513 while( cur.next() ) {
514 ... // process data
515 }
516 ...
517 cur.select(); // re-selects all records in department 10
518 ...
519 Examples:
521
523 This is an overloaded member function, provided for convenience. It
524 behaves essentially like the above function.
525 Selects all fields in the cursor from the database. The rows are
527 returned in the order specified by the last call to setSort() or the
528 last call to select() that specified a sort, whichever is the most
529 recent. If there is no current sort, the order in which the rows are
530 returned is undefined. The records are filtered according to the filter
531 specified by the last call to setFilter() or the last call to select()
532 that specified a filter, whichever is the most recent. If there is no
533 current filter, all records are returned. The cursor is initially
534 positioned at an invalid row. To move to a valid row, use seek(),
535 first(), last(), prev() or next().
536 See also setSort() and setFilter().
538
540 This is an overloaded member function, provided for convenience. It
541 behaves essentially like the above function.
542 Selects all fields in the cursor from the database. The data is
544 returned in the order specified by the index sort. The records are
545 filtered according to the filter specified by the last call to
546 setFilter() or the last call to select() that specified a filter,
547 whichever is the most recent. The cursor is initially positioned at an
548 invalid row. To move to a valid row, use seek(), first(), last(),
549 prev() or next().
550
552 This is an overloaded member function, provided for convenience. It
553 behaves essentially like the above function.
554 Selects all fields in the cursor matching the filter index filter. The
556 data is returned in the order specified by the index sort. The filter
557 index works by constructing a WHERE clause using the names of the
558 fields from the filter and their values from the current cursor record.
559 The cursor is initially positioned at an invalid row. To move to a
560 valid row, use seek(), first(), last(), prev() or next(). This function
561 is useful, for example, for retrieving data based upon a table's
562 primary index:
563 QSqlCursor cur( "Employee" );
565 QSqlIndex pk = cur.primaryIndex();
566 cur.setValue( "id", 10 );
567 cur.select( pk, pk ); // generates "SELECT ... FROM Employee WHERE id=10 ORDER BY id"
568 ...
569 In this example the QSqlIndex, pk, is used for two different purposes.
571 When used as the filter (first) argument, the field names it contains
572 are used to construct the WHERE clause, each set to the current cursor
573 value, WHERE id=10, in this case. When used as the sort (second)
574 argument the field names it contains are used for the ORDER BY clause,
575 ORDER BY id in this example.
576
578 [virtual]
579 Sets field name to calculated. If the field name does not exist,
580 nothing happens. The value of a calculated field is set by the
581 calculateField() virtual function which you must reimplement (or the
582 field value will be an invalid QVariant). Calculated fields do not
583 appear in generated SQL statements sent to the database.
584 See also calculateField() and QSqlRecord::setGenerated().
586
588 Sets the current filter to filter. Note that no new records are
589 selected. To select new records, use select(). The filter will apply to
590 any subsequent select() calls that do not explicitly specify a filter.
591 The filter is a SQL WHERE clause without the keyword 'WHERE', e.g.
593 name='Dave' which will be processed by the DBMS.
594
596 [virtual]
597 Sets the generated flag for the field name to generated. If the field
598 does not exist, nothing happens. Only fields that have generated set to
599 TRUE are included in the SQL that is generated by insert(), update() or
600 del().
601 See also isGenerated().
603 Reimplemented from QSqlRecord.
605
607 This is an overloaded member function, provided for convenience. It
608 behaves essentially like the above function.
609 Sets the generated flag for the field i to generated.
611 See also isGenerated().
613 Reimplemented from QSqlRecord.
615
617 Sets the cursor mode to mode. This value can be an OR'ed combination of
618 QSqlCursor::Mode values. The default mode for a cursor is
619 QSqlCursor::Writable.
620 QSqlCursor cur( "Employee" );
622 cur.setMode( QSqlCursor::Writable ); // allow insert/update/delete
623 ...
624 cur.setMode( QSqlCursor::Insert | QSqlCursor::Update ); // allow inserts and updates only
625 ...
626 cur.setMode( QSqlCursor::ReadOnly ); // no inserts/updates/deletes allowed
627
629 [virtual]
630 Sets the name of the cursor to name. If autopopulate is TRUE (the
631 default), the name must correspond to a valid table or view name in the
632 database. Also, note that all references to the cursor edit buffer
633 become invalidated when fields are auto-populated. See the QSqlCursor
634 constructor documentation for more information.
635
637 Sets the primary index associated with the cursor to the index idx.
638 Note that this index must contain a field or set of fields which
639 identify a unique record within the underlying database table or view
640 so that update() and del() will execute as expected.
641 See also update() and del().
643
645 Sets the current sort to sort. Note that no new records are selected.
646 To select new records, use select(). The sort will apply to any
647 subsequent select() calls that do not explicitly specify a sort.
648
650 Sets field name's trimmed status to trim. If the field name does not
651 exist, nothing happens.
652 When a trimmed field of type string or cstring is read from the
654 database any trailing (right-most) spaces are removed.
655 See also isTrimmed() and QVariant.
657
659 Returns the current sort, or an empty index if there is no current
660 sort.
661
663 QString & fieldSep, const QString & sep ) const [virtual protected]
664 Returns a formatted string composed of all the fields in rec. Each
665 field is composed of the prefix (e.g. table or view name)," prefix is
666 empty then each field will begin with the field name. The fields are
667 then joined together separated by sep. Fields where isGenerated()
668 returns FALSE are not included. This function is useful for generating
669 SQL statements.
670
672 const QString & fieldSep ) const [virtual protected]
673 This is an overloaded member function, provided for convenience. It
674 behaves essentially like the above function.
675 Returns a formatted string composed of the prefix (e.g. table or view
677 name), ".", the field name, the fieldSep and the field value. If the
678 prefix is empty then the string will begin with the field name. This
679 function is useful for generating SQL statements.
680
682 QString & prefix, const QString & fieldSep, const QString & sep ) const
683 [virtual protected]
684 This is an overloaded member function, provided for convenience. It
685 behaves essentially like the above function.
686 Returns a formatted string composed of all the fields in the index i.
688 Each field is composed of the prefix (e.g. table or view name), ".",
689 the field name, the fieldSep and the field value. If the prefix is
690 empty then each field will begin with the field name. The field values
691 are taken from rec. The fields are then joined together separated by
692 sep. Fields where isGenerated() returns FALSE are ignored. This
693 function is useful for generating SQL statements.
694
696 Updates the database with the current contents of the edit buffer.
697 Returns the number of records which were updated. For error
698 information, use lastError().
699 Only records which meet the filter criteria specified by the cursor's
701 primary index are updated. If the cursor does not contain a primary
702 index, no update is performed and 0 is returned.
703 If invalidate is TRUE (the default), the current cursor can no longer
705 be navigated. A new select() call must be made before you can move to a
706 valid record. For example:
707 QSqlCursor cur( "prices" );
709 cur.select( "id=202" );
710 if ( cur.next() ) {
711 QSqlRecord *buffer = cur.primeUpdate();
712 double price = buffer->value( "price" ).toDouble();
713 double newprice = price * 1.05;
714 buffer->setValue( "price", newprice );
715 cur.update();
716 }
717 In the above example, a cursor is created on the 'prices' table and is
719 positioned on the record to be updated. Then a pointer to the cursor's
720 edit buffer is acquired using primeUpdate(). A new value is calculated
721 and placed into the edit buffer with the setValue() call. Finally, an
722 update() call is made on the cursor which uses the tables's primary
723 index to update the record in the database with the contents of the
724 cursor's edit buffer. Remember: all edit operations (insert(), update()
725 and delete()) operate on the contents of the cursor edit buffer and not
726 on the contents of the cursor itself.
727 Note that if the primary index does not uniquely distinguish records
729 the database may be changed into an inconsistent state.
730 See also setMode() and lastError().
732 Example: sql/overview/update/main.cpp.
734
736 [virtual protected]
737 This is an overloaded member function, provided for convenience. It
738 behaves essentially like the above function.
739 Updates the database with the current contents of the cursor edit
741 buffer using the specified filter. Returns the number of records which
742 were updated. For error information, use lastError().
743 Only records which meet the filter criteria are updated, otherwise all
745 records in the table are updated.
746 If invalidate is TRUE (the default), the cursor can no longer be
748 navigated. A new select() call must be made before you can move to a
749 valid record.
750 See also primeUpdate(), setMode(), and lastError().
752
755 http://doc.trolltech.com/qsqlcursor.html
756 http://www.trolltech.com/faq/tech.html
757
759 Copyright 1992-2007 Trolltech ASA, http://www.trolltech.com. See the
760 license file included in the distribution for a complete license
761 statement.
762
764 Generated automatically from the source code.
765
767 If you find a bug in Qt, please report it as described in
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769 help you. Thank you.
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780Trolltech AS 2 February 2007 QSqlCursor(3qt)