Table of Contents
VCursor Class: ODBC Navigation Methods
This group of methods implements “old good” style of records navigation in cursor (recordset). It provides shortest possible notation for move-forward after cursor creation, thanks to WHILE() loop.
It is important to remember, that these methods assume that the current position in cursor can be
- BEFORE the first record
- AFTER the last record
Right after the creation of a cursor the position is BEFORE the first record. So ( NextRecord_ODBC() ) will move us to the first record if it exists.
NOTE: Actually NextRecord_ODBC() method will be used in 99% cases. All the rest methods in this group was made just for symmetry with the main group of navigation methods of a Valentina Cursor.
NOTE: VCursor.EOF and Cursor.BOF properties are players of this group also.
VCursor.FirstRecord_ODBC()
Declaration:
FirstRecord_ODBC() as Boolean
Description:
This form of FirstRecord() can work with “BEFORE THE FIRST” and “AFTER THE LAST” positions.
Go to the first logical record of a Cursor. Returns TRUE if the first record was found.
Example:
res = curs.FirstRecord_ODBC()
VCursor.LastRecord_ODBC()
Declaration:
This form of LastRecord() can work with “BEFORE THE FIRST” and “AFTER THE LAST” positions.
LastRecord_ODBC() as Boolean
Description:
Go to the last record of a Cursor. Returns TRUE if the last record was found.
Example:
res = curs.LastRecord_ODBC()
VCursor.PrevRecord_ODBC()
This form of PrevRecord() can work with “BEFORE THE FIRST” and “AFTER THE LAST” positions.
Declaration:
PrevRecord_ODBC() as Boolean
Description:
Go to the previous record of a Cursor if it exists.
- Returns TRUE if the previous record is found (i.e. the current position was changed).
- Returns FALSE if the current record was already the first or the Cursor is empty.
Example:
res = curs.PrevRecord_ODBC()
VCursor.NextRecord_ODBC()
NextRecord_ODBC() as Boolean
Description:
This form of NextRecord() can work with “BEFORE THE FIRST” and “AFTER THE LAST” positions.
Just after creation of a cursor, we are BEFORE the first record. So NextRecord_ODBC() moves us to the first record of cursor if it exists.
- Returns TRUE if the next record is found (i.e. the current position was changed).
- Returns FALSE if the current record was already the last or the Cursor is empty.
Example:
curs = db.SqlSelect( "SELECT * FROM T" ) while( curs.NextRecord_ODBC() ) { ... }