Btrieve Interview Questions and Answers
What is Btrieve?
- Btrieve is a navigational database product
- Based on Indexed Sequential Access Method(ISAM)
- ISAM is a way of fast data retrieval
- Btrieve retrieves one record at a time.
- Transaction Operation is faster as there is little overhead with Btrieve Engine
Define a C long integer as a key in Btrieve, when there is no long data type?
C long integer can be defined as a key in Btrieve by specifying the key as an integer. But the length need to be specified as four bytes.
How can a Btrieve file format version be checked? In other words, how can someone determine whether a Btrieve file is stored in 5.x or 6.x format?
The process is as follows:
- Run the BUTIL NLM version 6.x from the file server, which displays the version of file format after executing a STAT call.
- No client BUTIL program is available to display this status
- Another way is to check the version format of a Btrieve file by using DOS DEBUG utility
- Type debug-d at DOS prompt.
- The initial two bytes of the FCR will be set to FC when the file is stored in 6.x format.
- Otherwise the bytes will be set to 0x00.
What is status 1015?
- Prior to starting the application, if the environment variable SET BTRPARMSCHK=Y is specified, the status 1015 is returned.
- Isolation of errors that are caused by passing invalid pointers to Btrieve is done by using this environment variable.
- Once this variable is set, Btrieve performs the validation on pointer parameters that are passed in to READ/WRITE access on certain ranges.
- Btrieve validates position block pointer on the range of 128 bytes, length pointer validates on two bytes and data buffer is validated on 255 bytes for key buffer
Explain about File sharing?
- Data available in a file can be shared by using Single Engine File Sharing and Multiple Engine File Sharing modes.
- SEFS is allowed only to the clients to access the engine for altering databases.
- MEFS allows multiple clients running under multiple engines for accessing the database.