btestvlr.py

This is an example of variable length records based on btest.py .

import sys
import struct
import math
import os
import platform
 
if (platform.system() == "Windows"):
    sys.path.append("C:\\Program Files\\Actian\\Zen\\bin")
else:
    sys.path.append("/usr/local/actianzen/lib64")
 
import btrievePython
 
min_x = 0
max_x = 255
btrieveFileName = "squaresAndSquareRoots.btr"
recordFormat = "<BHd"
recordFixedSize = 11
recordMaximumVariableSize = 1024
recordMaximumTotalSize = recordFixedSize + recordMaximumVariableSize
keyFormat = "<B"
 
# If the incorrect number of arguments were given.
if (len(sys.argv) != 2):
    sys.exit("Usage: " + os.path.basename(sys.argv[0]) + " uint8_value")
 
integerValue = int(sys.argv[1])
 
# If integerValue is out of range.
if (integerValue < min_x) or (integerValue > max_x):
    sys.exit("Usage: " + os.path.basename(sys.argv[0]) + " uint8_value")
 
btrieveClient = btrievePython.BtrieveClient()
assert(btrieveClient != None)
 
btrieveFileAttributes = btrievePython.BtrieveFileAttributes()
assert(btrieveFileAttributes != None)
 
rc = btrieveFileAttributes.SetFixedRecordLength(recordFixedSize)
assert(rc == btrievePython.Btrieve.STATUS_CODE_NO_ERROR), "Error: BtrieveFileAttributes::SetFixedRecordLength():%d:%s.\n" % (rc, btrievePython.Btrieve_StatusCodeToString(rc))
 
rc = btrieveFileAttributes.SetVariableLengthRecordsMode(btrievePython.Btrieve.VARIABLE_LENGTH_RECORDS_MODE_YES)
assert(rc == btrievePython.Btrieve.STATUS_CODE_NO_ERROR), "Error: BtrieveFileAttributes::SetVariableLengthRecordsMode():%d:%s.\n" % (rc, btrievePython.Btrieve_StatusCodeToString(rc))
 
rc = btrieveClient.FileCreate(btrieveFileAttributes, btrieveFileName, btrievePython.Btrieve.CREATE_MODE_OVERWRITE)
assert(rc == btrievePython.Btrieve.STATUS_CODE_NO_ERROR), "Error: BtrieveClient::FileCreate():%d:%s.\n" % (rc, btrievePython.Btrieve_StatusCodeToString(rc))
 
btrieveFile = btrievePython.BtrieveFile()
assert(btrieveFile != None)
 
rc = btrieveClient.FileOpen(btrieveFile, btrieveFileName, None, btrievePython.Btrieve.OPEN_MODE_NORMAL)
assert(rc == btrievePython.Btrieve.STATUS_CODE_NO_ERROR), "Error: BtrieveClient::FileOpen():%d:%s.\n" % (rc, btrievePython.Btrieve_StatusCodeToString(rc))
 
# For all the values of x.
for i in range(min_x, max_x + 1):
    iSquared = i * i
    iSquareRoot = math.sqrt(i)
    text = "The square of " + str(i) + " is " + str(iSquared) + " and its square root is " + str(iSquareRoot) + "."
    variableRecordFormat = recordFormat + str(len(text)) + "s"
    record = struct.pack(variableRecordFormat, i, iSquared, iSquareRoot, bytes(text, "utf-8"))
 
    rc = btrieveFile.RecordCreate(record)
    assert(rc == btrievePython.Btrieve.STATUS_CODE_NO_ERROR), "Error: BtrieveFile::RecordCreate():%d:%s.\n"  % (rc, btrievePython.Btrieve_StatusCodeToString(rc))
 
btrieveKeySegment = btrievePython.BtrieveKeySegment()
assert(btrieveKeySegment != None)
 
rc = btrieveKeySegment.SetField(0, 1, btrievePython.Btrieve.DATA_TYPE_UNSIGNED_BINARY)
assert(rc == btrievePython.Btrieve.STATUS_CODE_NO_ERROR), "Error: BtrieveKeySegment::SetField():%d:%s.\n" % (rc, btrievePython.Btrieve_StatusCodeToString(rc))
 
btrieveIndexAttributes = btrievePython.BtrieveIndexAttributes()
assert(btrieveIndexAttributes != None)
 
rc = btrieveIndexAttributes.AddKeySegment(btrieveKeySegment)
assert(rc == btrievePython.Btrieve.STATUS_CODE_NO_ERROR), "Error: BtrieveIndexAttributes::AddKeySegment():%d:%s.\n" % (rc, btrievePython.Btrieve_StatusCodeToString(rc))
 
rc = btrieveFile.IndexCreate(btrieveIndexAttributes)
assert(rc == btrievePython.Btrieve.STATUS_CODE_NO_ERROR), "Error: BtrieveFile::IndexCreate():%d:%s.\n" % (rc, btrievePython.Btrieve_StatusCodeToString(rc))
 
# print record
record = bytes(recordMaximumTotalSize)
key = struct.pack(keyFormat, integerValue)
 
rc = btrieveFile.RecordRetrieve(btrievePython.Btrieve.COMPARISON_EQUAL, btrievePython.Btrieve.INDEX_1, key, record)
assert(rc >= recordFixedSize), "Error: BtrieveFile::RecordRetrieve():%d:%s.\n" % (rc, btrievePython.Btrieve_StatusCodeToString(btrieveFile.GetLastStatusCode()))
 
variableRecordFormat = recordFormat + str(rc - recordFixedSize) + "s"
i, iSquared, iSquareRoot, text = struct.unpack_from(variableRecordFormat, record)
print("record: ({}, {}, {}, {})".format(i, iSquared, iSquareRoot, str(text, "utf-8")))
 
rc = btrieveClient.FileClose(btrieveFile)
assert(rc == btrievePython.Btrieve.STATUS_CODE_NO_ERROR), "Error: BtrieveClient::FileClose():%d:%s.\n" % (rc, btrievePython.Btrieve_StatusCodeToString(rc))
 
rc = btrieveClient.FileDelete(btrieveFileName)
assert(rc == btrievePython.Btrieve.STATUS_CODE_NO_ERROR), "Error: BtrieveClient::FileDelete():%d:%s.\n" % (rc, btrievePython.Btrieve_StatusCodeToString(rc))