Get Less Than or Equal (11)

The Get Less Than or Equal operation (B_GET_LE) retrieves a record in which the value for the key specified by the Key Number has an equal or a previous lesser value than the value you supply in the Key Buffer. The MicroKernel first tries to satisfy the equal requirement. If the key allows duplicate values, this operation retrieves the last record (chronologically) of the group with the same key values. You can use the Get Key (+50) bias to detect the presence of a value in a file. A Get Key operation is generally faster.

Note
If you are using the Get Less Than or Equal operation on descending keys, the next lesser value refers to a value higher than the one specified in the Key Buffer.

Parameters


	Op Code	Pos Block	Data Buf	Data Buf Len	Key Buffer	Key Number
Sent
Returned

Prerequisites

The file must be open.

The file cannot be a data-only file.

Procedure

Set the Operation Code to 11. Optionally, you can include a lock bias:

+100-Single wait record lock.

+200-Single no-wait record lock.

+300-Multiple wait record lock.

+400-Multiple no-wait record lock.

For more information about locking, refer to the Pervasive.SQL Programmer's Guide.

Pass the Position Block for the file.

Set the Data Buffer Length to a value greater than or equal to the length of the record you want to retrieve.

Specify the key value in the Key Buffer parameter.

Set the Key Number parameter to the key path. To use the system-defined log key (also called system data), specify 125.

Result

If the Get Less Than or Equal operation is successful, the MicroKernel returns the record in the Data Buffer, the key value for the record in the Key Buffer, and the length of the record in the Data Buffer Length parameter.

If the Get Less Than or Equal operation is unsuccessful, the MicroKernel returns one of the following status codes:


3	The file is not open.
6	The key number parameter is invalid.
22	The data buffer parameter is too short.

Positioning

The Get Less Than or Equal operation establishes the complete logical and physical currencies and makes the retrieved record the current one.