From 5fffa30386502b5423e45c2ed5e6af756b11c7b4 Mon Sep 17 00:00:00 2001 From: Michele Calgaro Date: Tue, 28 May 2024 10:17:01 +0900 Subject: Rename nt* sql related files to equivalent tq* Signed-off-by: Michele Calgaro --- doc/html/ntqsqlcursor.html | 761 --------------------------------------------- 1 file changed, 761 deletions(-) delete mode 100644 doc/html/ntqsqlcursor.html (limited to 'doc/html/ntqsqlcursor.html') diff --git a/doc/html/ntqsqlcursor.html b/doc/html/ntqsqlcursor.html deleted file mode 100644 index e0aa1ff2f..000000000 --- a/doc/html/ntqsqlcursor.html +++ /dev/null @@ -1,761 +0,0 @@ - - - - - -TQSqlCursor Class - - - - - - - -
- -Home - | -All Classes - | -Main Classes - | -Annotated - | -Grouped Classes - | -Functions -

TQSqlCursor Class Reference
[sql module]

- -

The TQSqlCursor class provides browsing and editing of SQL -tables and views. -More... -

#include <ntqsqlcursor.h> -

Inherits TQSqlRecord and TQSqlQuery. -

Inherited by TQSqlSelectCursor. -

List of all member functions. -

Public Members

- -

Protected Members

- -

Detailed Description

- - -The TQSqlCursor class provides browsing and editing of SQL -tables and views. -

- -

A TQSqlCursor is a database record (see TQSqlRecord) that -corresponds to a table or view within an SQL database (see TQSqlDatabase). There are two buffers in a cursor, one used for -browsing and one used for editing records. Each buffer contains a -list of fields which correspond to the fields in the table or -view. -

When positioned on a valid record, the browse buffer contains the -values of the current record's fields from the database. The edit -buffer is separate, and is used for editing existing records and -inserting new records. -

For browsing data, a cursor must first select() data from the -database. After a successful select() the cursor is active -(isActive() returns TRUE), but is initially not positioned on a -valid record (isValid() returns FALSE). To position the cursor on -a valid record, use one of the navigation functions, next(), -prev(), first(), last(), or seek(). Once positioned on a valid -record, data can be retrieved from the browse buffer using -value(). If a navigation function is not successful, it returns -FALSE, the cursor will no longer be positioned on a valid record -and the values returned by value() are undefined. -

For example: -

- -

            TQSqlCursor cur( "staff" ); // Specify the table/view name
-            cur.select(); // We'll retrieve every record
-            while ( cur.next() ) {
-                tqDebug( cur.value( "id" ).toString() + ": " +
-                        cur.value( "surname" ).toString() + " " +
-                        cur.value( "salary" ).toString() );
-            }
-
-

In the above example, a cursor is created specifying a table or -view name in the database. Then, select() is called, which can be -optionally parameterised to filter and order the records -retrieved. Each record in the cursor is retrieved using next(). -When next() returns FALSE, there are no more records to process, -and the loop terminates. -

For editing records (rows of data), a cursor contains a separate -edit buffer which is independent of the fields used when browsing. -The functions insert(), update() and del() operate on the edit -buffer. This allows the cursor to be repositioned to other -records while simultaneously maintaining a separate buffer for -edits. You can get a pointer to the edit buffer using -editBuffer(). The primeInsert(), primeUpdate() and primeDelete() -functions also return a pointer to the edit buffer and prepare it -for insert, update and delete respectively. Edit operations only -affect a single row at a time. Note that update() and del() -require that the table or view contain a primaryIndex() to ensure -that edit operations affect a unique record within the database. -

For example: -

- -

            TQSqlCursor cur( "prices" );
-            cur.select( "id=202" );
-            if ( cur.next() ) {
-                TQSqlRecord *buffer = cur.primeUpdate();
-                double price = buffer->value( "price" ).toDouble();
-                double newprice = price * 1.05;
-                buffer->setValue( "price", newprice );
-                cur.update();
-            }
-
-

To edit an existing database record, first move to the record you -wish to update. Call primeUpdate() to get the pointer to the -cursor's edit buffer. Then use this pointer to modify the values -in the edit buffer. Finally, call update() to save the changes to -the database. The values in the edit buffer will be used to -locate the appropriate record when updating the database (see -primaryIndex()). -

Similarly, when deleting an existing database record, first move -to the record you wish to delete. Then, call primeDelete() to get -the pointer to the edit buffer. Finally, call del() to delete the -record from the database. Again, the values in the edit buffer -will be used to locate and delete the appropriate record. -

To insert a new record, call primeInsert() to get the pointer to -the edit buffer. Use this pointer to populate the edit buffer -with new values and then insert() the record into the database. -

After calling insert(), update() or del(), the cursor is no longer -positioned on a valid record and can no longer be navigated -(isValid() return FALSE). The reason for this is that any changes -made to the database will not be visible until select() is called -to refresh the cursor. You can change this behavior by passing -FALSE to insert(), update() or del() which will prevent the cursor -from becoming invalid. The edits will still not be visible when -navigating the cursor until select() is called. -

TQSqlCursor contains virtual methods which allow editing behavior -to be customized by subclasses. This allows custom cursors to be -created that encapsulate the editing behavior of a database table -for an entire application. For example, a cursor can be customized -to always auto-number primary index fields, or provide fields with -suitable default values, when inserting new records. TQSqlCursor -generates SQL statements which are sent to the database engine; -you can control which fields are included in these statements -using setGenerated(). -

Note that TQSqlCursor does not inherit from TQObject. This means -that you are responsible for destroying instances of this class -yourself. However if you create a TQSqlCursor and use it in a -TQDataTable, TQDataBrowser or a TQDataView these classes will -usually take ownership of the cursor and destroy it when they -don't need it anymore. The documentation for TQDataTable, -TQDataBrowser and TQDataView explicitly states which calls take -ownership of the cursor. -

See also Database Classes. - -

Member Type Documentation

-

TQSqlCursor::Mode

- -

This enum type describes how TQSqlCursor operates on records in the -database. -

-

Member Function Documentation

-

TQSqlCursor::TQSqlCursor ( const TQString & name = TQString::null, bool autopopulate = TRUE, TQSqlDatabase * db = 0 ) -

-Constructs a cursor on database db using table or view name. -

If autopopulate is TRUE (the default), the name of the -cursor must correspond to an existing table or view name in the -database so that field information can be automatically created. -If the table or view does not exist, the cursor will not be -functional. -

The cursor is created with an initial mode of TQSqlCursor::Writable -(meaning that records can be inserted, updated or deleted using -the cursor). If the cursor does not have a unique primary index, -update and deletes cannot be performed. -

Note that autopopulate refers to populating the cursor with -meta-data, e.g. the names of the table's fields, not with -retrieving data. The select() function is used to populate the -cursor with data. -

See also setName() and setMode(). - -

TQSqlCursor::TQSqlCursor ( const TQSqlCursor & other ) -

-Constructs a copy of other. - -

TQSqlCursor::~TQSqlCursor () -

-Destroys the object and frees any allocated resources. - -

void TQSqlCursor::append ( const TQSqlFieldInfo & fieldInfo ) [virtual] -

-Append a copy of field fieldInfo to the end of the cursor. Note -that all references to the cursor edit buffer become invalidated. - -

TQVariant TQSqlCursor::calculateField ( const TQString & name ) [virtual protected] -

-Protected virtual function which is called whenever a field needs -to be calculated. If calculated fields are being used, derived -classes must reimplement this function and return the appropriate -value for field name. The default implementation returns an -invalid TQVariant. -

See also setCalculated(). - -

Examples: sql/overview/subclass3/main.cpp and sql/overview/subclass4/main.cpp. -

bool TQSqlCursor::canDelete () const -

-Returns TRUE if the cursor will perform deletes; otherwise returns -FALSE. -

See also setMode(). - -

bool TQSqlCursor::canInsert () const -

-Returns TRUE if the cursor will perform inserts; otherwise returns -FALSE. -

See also setMode(). - -

bool TQSqlCursor::canUpdate () const -

-Returns TRUE if the cursor will perform updates; otherwise returns -FALSE. -

See also setMode(). - -

void TQSqlCursor::clear () [virtual] -

-Removes all fields from the cursor. Note that all references to -the cursor edit buffer become invalidated. - -

Reimplemented from TQSqlRecord. -

int TQSqlCursor::del ( bool invalidate = TRUE ) [virtual] -

-Deletes a record from the database using the cursor's primary -index and the contents of the cursor edit buffer. Returns the -number of records which were deleted. -For error information, use lastError(). -

Only records which meet the filter criteria specified by the -cursor's primary index are deleted. If the cursor does not contain -a primary index, no delete is performed and 0 is returned. If invalidate is TRUE (the default), the current cursor can no longer -be navigated. A new select() call must be made before you can move -to a valid record. For example: -

- -

            TQSqlCursor cur( "prices" );
-            cur.select( "id=999" );
-            if ( cur.next() ) {
-                cur.primeDelete();
-                cur.del();
-            }
-
-

In the above example, a cursor is created on the 'prices' table -and positioned to the record to be deleted. First primeDelete() is -called to populate the edit buffer with the current cursor values, -e.g. with an id of 999, and then del() is called to actually -delete the record from the database. Remember: all edit operations -(insert(), update() and delete()) operate on the contents of the -cursor edit buffer and not on the contents of the cursor itself. -

See also primeDelete(), setMode(), and lastError(). - -

Example: sql/overview/delete/main.cpp. -

int TQSqlCursor::del ( const TQString & filter, bool invalidate = TRUE ) [virtual protected] -

-This is an overloaded member function, provided for convenience. It behaves essentially like the above function. -

Deletes the current cursor record from the database using the -filter filter. Only records which meet the filter criteria are -deleted. Returns the number of records which were deleted. If invalidate is TRUE (the default), the current cursor can no longer -be navigated. A new select() call must be made before you can move -to a valid record. For error information, use lastError(). -

The filter is an SQL WHERE clause, e.g. id=500. -

See also setMode() and lastError(). - -

TQSqlRecord * TQSqlCursor::editBuffer ( bool copy = FALSE ) [virtual] -

-Returns the current internal edit buffer. If copy is TRUE (the -default is FALSE), the current cursor field values are first -copied into the edit buffer. The edit buffer is valid as long as -the cursor remains valid. The cursor retains ownership of the -returned pointer, so it must not be deleted or modified. -

See also primeInsert(), primeUpdate(), and primeDelete(). - -

TQString TQSqlCursor::filter () const -

-Returns the current filter, or an empty string if there is no -current filter. - -

TQSqlIndex TQSqlCursor::index ( const TQStringList & fieldNames ) const [virtual] -

-Returns an index composed of fieldNames, all in ASCending -order. Note that all field names must exist in the cursor, -otherwise an empty index is returned. -

See also TQSqlIndex. - -

Examples: sql/overview/extract/main.cpp, sql/overview/order1/main.cpp, sql/overview/order2/main.cpp, and sql/overview/table3/main.cpp. -

TQSqlIndex TQSqlCursor::index ( const TQString & fieldName ) const -

-This is an overloaded member function, provided for convenience. It behaves essentially like the above function. -

Returns an index based on fieldName. - -

TQSqlIndex TQSqlCursor::index ( const char * fieldName ) const -

-This is an overloaded member function, provided for convenience. It behaves essentially like the above function. -

Returns an index based on fieldName. - -

void TQSqlCursor::insert ( int pos, const TQSqlFieldInfo & fieldInfo ) [virtual] -

-Insert a copy of fieldInfo at position pos. If a field -already exists at pos, it is removed. Note that all references -to the cursor edit buffer become invalidated. - -

Examples: sql/overview/insert/main.cpp and sql/overview/insert2/main.cpp. -

int TQSqlCursor::insert ( bool invalidate = TRUE ) [virtual] -

-This is an overloaded member function, provided for convenience. It behaves essentially like the above function. -

Inserts the current contents of the cursor's edit record buffer -into the database, if the cursor allows inserts. Returns the -number of rows affected by the insert. For error information, use -lastError(). -

If invalidate is TRUE (the default), the cursor will no longer -be positioned on a valid record and can no longer be navigated. A -new select() call must be made before navigating to a valid -record. -

- -

            TQSqlCursor cur( "prices" );
-            TQSqlRecord *buffer = cur.primeInsert();
-            buffer->setValue( "id",    53981 );
-            buffer->setValue( "name",  "Thingy" );
-            buffer->setValue( "price", 105.75 );
-            cur.insert();
-
-

In the above example, a cursor is created on the 'prices' table -and a pointer to the insert buffer is acquired using primeInsert(). -Each field's value is set to the desired value and then insert() -is called to insert the data into the database. Remember: all edit -operations (insert(), update() and delete()) operate on the -contents of the cursor edit buffer and not on the contents of the -cursor itself. -

See also setMode() and lastError(). - -

bool TQSqlCursor::isCalculated ( const TQString & name ) const -

-Returns TRUE if the field name exists and is calculated; -otherwise returns FALSE. -

See also setCalculated(). - -

bool TQSqlCursor::isNull ( int i ) const -

-Returns TRUE if the field i is NULL or if there is no field at -position i; otherwise returns FALSE. -

This is the same as calling TQSqlRecord::isNull( i ) - -

bool TQSqlCursor::isNull ( const TQString & name ) const -

-This is an overloaded member function, provided for convenience. It behaves essentially like the above function. -

Returns TRUE if the field called name is NULL or if there is no -field called name; otherwise returns FALSE. -

This is the same as calling TQSqlRecord::isNull( name ) - -

bool TQSqlCursor::isReadOnly () const -

-Returns TRUE if the cursor is read-only; otherwise returns FALSE. -The default is FALSE. Read-only cursors cannot be edited using -insert(), update() or del(). -

See also setMode(). - -

bool TQSqlCursor::isTrimmed ( const TQString & name ) const -

-Returns TRUE if the field name exists and is trimmed; otherwise -returns FALSE. -

When a trimmed field of type string or cstring is read from the -database any trailing (right-most) spaces are removed. -

See also setTrimmed(). - -

int TQSqlCursor::mode () const -

-Returns the current cursor mode. -

See also setMode(). - -

TQString TQSqlCursor::name () const -

-Returns the name of the cursor. - -

TQSqlCursor & TQSqlCursor::operator= ( const TQSqlCursor & other ) -

-Sets the cursor equal to other. - -

TQSqlIndex TQSqlCursor::primaryIndex ( bool setFromCursor = TRUE ) const [virtual] -

-Returns the primary index associated with the cursor as defined in -the database, or an empty index if there is no primary index. If -setFromCursor is TRUE (the default), the index fields are -populated with the corresponding values in the cursor's current -record. - -

TQSqlRecord * TQSqlCursor::primeDelete () [virtual] -

-This function primes the edit buffer's field values for delete and -returns the edit buffer. The default implementation copies the -field values from the current cursor record into the edit buffer -(therefore, this function is equivalent to calling editBuffer( -TRUE ) ). The cursor retains ownership of the returned pointer, so -it must not be deleted or modified. -

See also editBuffer() and del(). - -

Example: sql/overview/delete/main.cpp. -

TQSqlRecord * TQSqlCursor::primeInsert () [virtual] -

-This function primes the edit buffer's field values for insert and -returns the edit buffer. The default implementation clears all -field values in the edit buffer. The cursor retains ownership of -the returned pointer, so it must not be deleted or modified. -

See also editBuffer() and insert(). - -

Examples: sql/overview/insert/main.cpp, sql/overview/insert2/main.cpp, sql/overview/subclass5/main.cpp, and sql/sqltable/main.cpp. -

TQSqlRecord * TQSqlCursor::primeUpdate () [virtual] -

-This function primes the edit buffer's field values for update and -returns the edit buffer. The default implementation copies the -field values from the current cursor record into the edit buffer -(therefore, this function is equivalent to calling editBuffer( -TRUE ) ). The cursor retains ownership of the returned pointer, so -it must not be deleted or modified. -

See also editBuffer() and update(). - -

Examples: sql/overview/custom1/main.cpp, sql/overview/form1/main.cpp, and sql/overview/update/main.cpp. -

void TQSqlCursor::remove ( int pos ) [virtual] -

-Removes the field at pos. If pos does not exist, nothing -happens. Note that all references to the cursor edit buffer become -invalidated. - -

Reimplemented from TQSqlRecord. -

bool TQSqlCursor::select ( const TQString & filter, const TQSqlIndex & sort = TQSqlIndex ( ) ) [virtual] -

-Selects all fields in the cursor from the database matching the -filter criteria filter. The data is returned in the order -specified by the index sort. Returns TRUE if the data was -successfully selected; otherwise returns FALSE. -

The filter is a string containing a SQL WHERE clause but -without the 'WHERE' keyword. The cursor is initially positioned at -an invalid row after this function is called. To move to a valid -row, use seek(), first(), last(), prev() or next(). -

Example: -

-    TQSqlCursor cur( "Employee" ); // Use the Employee table or view
-    cur.select( "deptno=10" ); // select all records in department 10
-    while( cur.next() ) {
-        ... // process data
-    }
-    ...
-    // select records in other departments, ordered by department number
-    cur.select( "deptno>10", cur.index( "deptno" ) );
-    ...
-
- -

The filter will apply to any subsequent select() calls that do not -explicitly specify another filter. Similarly the sort will apply -to any subsequent select() calls that do not explicitly specify -another sort. -

-    TQSqlCursor cur( "Employee" );
-    cur.select( "deptno=10" ); // select all records in department 10
-    while( cur.next() ) {
-        ... // process data
-    }
-    ...
-    cur.select(); // re-selects all records in department 10
-    ...
-
- -

-

Examples: sql/overview/delete/main.cpp, sql/overview/extract/main.cpp, sql/overview/order1/main.cpp, sql/overview/order2/main.cpp, sql/overview/retrieve2/main.cpp, sql/overview/table3/main.cpp, and sql/overview/update/main.cpp. -

bool TQSqlCursor::select () -

-This is an overloaded member function, provided for convenience. It behaves essentially like the above function. -

Selects all fields in the cursor from the database. The rows are -returned in the order specified by the last call to setSort() or -the last call to select() that specified a sort, whichever is the -most recent. If there is no current sort, the order in which the -rows are returned is undefined. The records are filtered according -to the filter specified by the last call to setFilter() or the -last call to select() that specified a filter, whichever is the -most recent. If there is no current filter, all records are -returned. The cursor is initially positioned at an invalid row. To -move to a valid row, use seek(), first(), last(), prev() or -next(). -

See also setSort() and setFilter(). - -

bool TQSqlCursor::select ( const TQSqlIndex & sort ) -

-This is an overloaded member function, provided for convenience. It behaves essentially like the above function. -

Selects all fields in the cursor from the database. The data is -returned in the order specified by the index sort. The records -are filtered according to the filter specified by the last call to -setFilter() or the last call to select() that specified a filter, -whichever is the most recent. The cursor is initially positioned -at an invalid row. To move to a valid row, use seek(), first(), -last(), prev() or next(). - -

bool TQSqlCursor::select ( const TQSqlIndex & filter, const TQSqlIndex & sort ) -

-This is an overloaded member function, provided for convenience. It behaves essentially like the above function. -

Selects all fields in the cursor matching the filter index filter. The data is returned in the order specified by the index -sort. The filter index works by constructing a WHERE clause -using the names of the fields from the filter and their values -from the current cursor record. The cursor is initially positioned -at an invalid row. To move to a valid row, use seek(), first(), -last(), prev() or next(). This function is useful, for example, -for retrieving data based upon a table's primary index: -

-    TQSqlCursor cur( "Employee" );
-    TQSqlIndex pk = cur.primaryIndex();
-    cur.setValue( "id", 10 );
-    cur.select( pk, pk ); // generates "SELECT ... FROM Employee WHERE id=10 ORDER BY id"
-    ...
-
- -

In this example the TQSqlIndex, pk, is used for two different -purposes. When used as the filter (first) argument, the field -names it contains are used to construct the WHERE clause, each set -to the current cursor value, WHERE id=10, in this case. When -used as the sort (second) argument the field names it contains are -used for the ORDER BY clause, ORDER BY id in this example. - -

void TQSqlCursor::setCalculated ( const TQString & name, bool calculated ) [virtual] -

-Sets field name to calculated. If the field name does not -exist, nothing happens. The value of a calculated field is set by -the calculateField() virtual function which you must reimplement -(or the field value will be an invalid TQVariant). Calculated -fields do not appear in generated SQL statements sent to the -database. -

See also calculateField() and TQSqlRecord::setGenerated(). - -

void TQSqlCursor::setFilter ( const TQString & filter ) [virtual] -

-Sets the current filter to filter. Note that no new records are -selected. To select new records, use select(). The filter will -apply to any subsequent select() calls that do not explicitly -specify a filter. -

The filter is a SQL WHERE clause without the keyword 'WHERE', -e.g. name='Dave' which will be processed by the DBMS. - -

void TQSqlCursor::setGenerated ( const TQString & name, bool generated ) [virtual] -

-Sets the generated flag for the field name to generated. If -the field does not exist, nothing happens. Only fields that have -generated set to TRUE are included in the SQL that is -generated by insert(), update() or del(). -

See also isGenerated(). - -

Reimplemented from TQSqlRecord. -

void TQSqlCursor::setGenerated ( int i, bool generated ) [virtual] -

-This is an overloaded member function, provided for convenience. It behaves essentially like the above function. -

Sets the generated flag for the field i to generated. -

See also isGenerated(). - -

Reimplemented from TQSqlRecord. -

void TQSqlCursor::setMode ( int mode ) [virtual] -

-Sets the cursor mode to mode. This value can be an OR'ed -combination of TQSqlCursor::Mode values. The default mode for a -cursor is TQSqlCursor::Writable. -

-    TQSqlCursor cur( "Employee" );
-    cur.setMode( TQSqlCursor::Writable ); // allow insert/update/delete
-    ...
-    cur.setMode( TQSqlCursor::Insert | TQSqlCursor::Update ); // allow inserts and updates only
-    ...
-    cur.setMode( TQSqlCursor::ReadOnly ); // no inserts/updates/deletes allowed
-
-
- - -

void TQSqlCursor::setName ( const TQString & name, bool autopopulate = TRUE ) [virtual] -

-Sets the name of the cursor to name. If autopopulate is TRUE -(the default), the name must correspond to a valid table or -view name in the database. Also, note that all references to the -cursor edit buffer become invalidated when fields are -auto-populated. See the TQSqlCursor constructor documentation for -more information. - -

void TQSqlCursor::setPrimaryIndex ( const TQSqlIndex & idx ) [virtual] -

-Sets the primary index associated with the cursor to the index idx. Note that this index must contain a field or set of fields -which identify a unique record within the underlying database -table or view so that update() and del() will execute as expected. -

See also update() and del(). - -

void TQSqlCursor::setSort ( const TQSqlIndex & sort ) [virtual] -

-Sets the current sort to sort. Note that no new records are -selected. To select new records, use select(). The sort will -apply to any subsequent select() calls that do not explicitly -specify a sort. - -

void TQSqlCursor::setTrimmed ( const TQString & name, bool trim ) [virtual] -

-Sets field name's trimmed status to trim. If the field name does not exist, nothing happens. -

When a trimmed field of type string or cstring is read from the -database any trailing (right-most) spaces are removed. -

See also isTrimmed() and TQVariant. - -

TQSqlIndex TQSqlCursor::sort () const -

-Returns the current sort, or an empty index if there is no current -sort. - -

TQString TQSqlCursor::toString ( TQSqlRecord * rec, const TQString & prefix, const TQString & fieldSep, const TQString & sep ) const [virtual protected] -

-Returns a formatted string composed of all the fields in rec. -Each field is composed of the prefix (e.g. table or view name), -".", the field name, the fieldSep and the field value. If the -prefix is empty then each field will begin with the field name. -The fields are then joined together separated by sep. Fields -where isGenerated() returns FALSE are not included. This function -is useful for generating SQL statements. - -

TQString TQSqlCursor::toString ( const TQString & prefix, TQSqlField * field, const TQString & fieldSep ) const [virtual protected] -

-This is an overloaded member function, provided for convenience. It behaves essentially like the above function. -

Returns a formatted string composed of the prefix (e.g. table -or view name), ".", the field name, the fieldSep and the -field value. If the prefix is empty then the string will begin -with the field name. This function is useful for generating SQL -statements. - -

TQString TQSqlCursor::toString ( const TQSqlIndex & i, TQSqlRecord * rec, const TQString & prefix, const TQString & fieldSep, const TQString & sep ) const [virtual protected] -

-This is an overloaded member function, provided for convenience. It behaves essentially like the above function. -

Returns a formatted string composed of all the fields in the index -i. Each field is composed of the prefix (e.g. table or view -name), ".", the field name, the fieldSep and the field value. -If the prefix is empty then each field will begin with the field -name. The field values are taken from rec. The fields are then -joined together separated by sep. Fields where isGenerated() -returns FALSE are ignored. This function is useful for generating -SQL statements. - -

int TQSqlCursor::update ( bool invalidate = TRUE ) [virtual] -

-Updates the database with the current contents of the edit buffer. -Returns the number of records which were updated. -For error information, use lastError(). -

Only records which meet the filter criteria specified by the -cursor's primary index are updated. If the cursor does not contain -a primary index, no update is performed and 0 is returned. -

If invalidate is TRUE (the default), the current cursor can no -longer be navigated. A new select() call must be made before you -can move to a valid record. For example: -

- -

            TQSqlCursor cur( "prices" );
-            cur.select( "id=202" );
-            if ( cur.next() ) {
-                TQSqlRecord *buffer = cur.primeUpdate();
-                double price = buffer->value( "price" ).toDouble();
-                double newprice = price * 1.05;
-                buffer->setValue( "price", newprice );
-                cur.update();
-            }
-
-

In the above example, a cursor is created on the 'prices' table -and is positioned on the record to be updated. Then a pointer to -the cursor's edit buffer is acquired using primeUpdate(). A new -value is calculated and placed into the edit buffer with the -setValue() call. Finally, an update() call is made on the cursor -which uses the tables's primary index to update the record in the -database with the contents of the cursor's edit buffer. Remember: -all edit operations (insert(), update() and delete()) operate on -the contents of the cursor edit buffer and not on the contents of -the cursor itself. -

Note that if the primary index does not uniquely distinguish -records the database may be changed into an inconsistent state. -

See also setMode() and lastError(). - -

Example: sql/overview/update/main.cpp. -

int TQSqlCursor::update ( const TQString & filter, bool invalidate = TRUE ) [virtual protected] -

-This is an overloaded member function, provided for convenience. It behaves essentially like the above function. -

Updates the database with the current contents of the cursor edit -buffer using the specified filter. Returns the number of -records which were updated. -For error information, use lastError(). -

Only records which meet the filter criteria are updated, otherwise -all records in the table are updated. -

If invalidate is TRUE (the default), the cursor can no longer -be navigated. A new select() call must be made before you can move -to a valid record. -

See also primeUpdate(), setMode(), and lastError(). - - -

-This file is part of the TQt toolkit. -Copyright © 1995-2007 -Trolltech. All Rights Reserved.

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Copyright © 2007 -TrolltechTrademarks -
TQt 3.3.8
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