bpercentage.py

This is an example of record retrieve both by percentage and fraction written in Python.

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"
numberOfRecords = max_x - min_x + 1
recordFormat = "<BHd"
recordLength = 11
keyFormat = "<B"
 
# If the incorrect number of arguments were given.
if (len(sys.argv) != 1):
    sys.exit("Usage: " + os.path.basename(sys.argv[0]))
 
btrieveClient = btrievePython.BtrieveClient()
assert(btrieveClient != None)
 
# Create file.
btrieveFileAttributes = btrievePython.BtrieveFileAttributes()
assert(btrieveFileAttributes != None)
 
rc = btrieveFileAttributes.SetFixedRecordLength(recordLength)
assert(rc == btrievePython.Btrieve.STATUS_CODE_NO_ERROR), "Error: BtrieveFileAttributes::SetFixedRecordLength():%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))
 
# Open file.
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))
 
# Load file.
# For all the values of x.
for i in range(min_x, max_x + 1):
    record = struct.pack(recordFormat, i, i * i, math.sqrt(i))
 
    rc = btrieveFile.RecordCreate(record)
    assert(rc == btrievePython.Btrieve.STATUS_CODE_NO_ERROR), "Error: BtrieveFile::RecordCreate():%d:%s.\n"  % (rc, btrievePython.Btrieve_StatusCodeToString(rc))
 
# Create index.
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))
 
# Retrieve records.
record = struct.pack(recordFormat, 0, 0, 0)
 
rc = btrieveFile.RecordRetrieveFirst(btrievePython.Btrieve.INDEX_1, record)
assert(rc == recordLength), "Error: BtrieveFile::RecordRetrieveFirst():%d:%s.\n" % (rc, btrievePython.Btrieve_StatusCodeToString(btrieveFile.GetLastStatusCode()))
 
print ("First:", struct.unpack(recordFormat, record))
 
rc = btrieveFile.RecordRetrieveByPercentage(btrievePython.Btrieve.INDEX_1, 0, record)
assert(rc == recordLength), "Error: BtrieveFile::RecordRetrieveByPercentage():%d:%s.\n" % (rc, btrievePython.Btrieve_StatusCodeToString(btrieveFile.GetLastStatusCode()))
 
print ("ByPercentage: 0% record:", struct.unpack(recordFormat, record))
 
rc = btrieveFile.RecordRetrieveByFraction(btrievePython.Btrieve.INDEX_1, 0, numberOfRecords, record)
assert(rc == recordLength), "Error: BtrieveFile::RecordRetrieveByFraction():%d:%s.\n" % (rc, btrievePython.Btrieve_StatusCodeToString(btrieveFile.GetLastStatusCode()))
 
print ("ByFraction:", 0, "/", numberOfRecords, "record:", struct.unpack(recordFormat, record))
 
 
rc = btrieveFile.RecordRetrieveByPercentage(btrievePython.Btrieve.INDEX_1, 5000, record)
assert(rc == recordLength), "Error: BtrieveFile::RecordRetrieveByPercentage():%d:%s.\n" % (rc, btrievePython.Btrieve_StatusCodeToString(btrieveFile.GetLastStatusCode()))
 
 
print ("ByPercentage: 50% record:", struct.unpack(recordFormat, record))
 
 
rc = btrieveFile.RecordRetrieveByFraction(btrievePython.Btrieve.INDEX_1, int(numberOfRecords / 2), numberOfRecords, record)
assert(rc == recordLength), "Error: BtrieveFile::RecordRetrieveByFraction():%d:%s.\n" % (rc, btrievePython.Btrieve_StatusCodeToString(btrieveFile.GetLastStatusCode()))
 
 
print ("ByFraction:", int(numberOfRecords / 2), "/", numberOfRecords, "record:", struct.unpack(recordFormat, record))
 
 
cursorPosition = btrieveFile.GetCursorPosition()
assert(cursorPosition != -1), "Error: BtrieveFile::GetCursorPosition():%d:%s.\n" % (rc, btrievePython.Btrieve_StatusCodeToString(btrieveFile.GetLastStatusCode()))
 
 
 
rc = btrieveFile.RecordRetrieveLast(btrievePython.Btrieve.INDEX_1, record)
assert(rc == recordLength), "Error: BtrieveFile::RecordRetrieveLast():%d:%s.\n" % (rc, btrievePython.Btrieve_StatusCodeToString(btrieveFile.GetLastStatusCode()))
 
 
print ("Last:", struct.unpack(recordFormat, record))
 
rc = btrieveFile.RecordRetrieveByPercentage(btrievePython.Btrieve.INDEX_1, 10000, record)
assert(rc == recordLength), "Error: BtrieveFile::RecordRetrieveByPercentage():%d:%s.\n" % (rc, btrievePython.Btrieve_StatusCodeToString(btrieveFile.GetLastStatusCode()))
 
print ("ByPercentage: 100% record:", struct.unpack(recordFormat, record))
 
rc = btrieveFile.RecordRetrieveByFraction(btrievePython.Btrieve.INDEX_1, numberOfRecords, numberOfRecords, record)
assert(rc == recordLength), "Error: BtrieveFile::RecordRetrieveByFraction():%d:%s.\n" % (rc, btrievePython.Btrieve_StatusCodeToString(btrieveFile.GetLastStatusCode()))
 
print ("ByFraction:", numberOfRecords, "/", numberOfRecords, "record:", struct.unpack(recordFormat, record))
 
 
rc = btrieveFile.RecordRetrieveByCursorPosition(btrievePython.Btrieve.INDEX_1, cursorPosition, record)
assert(rc == recordLength), "Error: BtrieveFile::RecordRetrieveByCursorPosition():%d:%s.\n" % (rc, btrievePython.Btrieve_StatusCodeToString(btrieveFile.GetLastStatusCode()))
 
 
print ("ByCursorPosition: record:", struct.unpack(recordFormat, record))
keyValue = int((max_x - min_x) / 2)
key = struct.pack(keyFormat, keyValue)
 
 
percentage = btrieveFile.GetPercentage(btrievePython.Btrieve.INDEX_1, key)
assert(percentage != -1), "Error: BtrieveFile::GetPercentage():%d:%s.\n" % (rc, btrievePython.Btrieve_StatusCodeToString(btrieveFile.GetLastStatusCode()))
 
 
print ("GetPercentage using Index:", percentage / 100, "%% key:", keyValue)
 
 
percentage = btrieveFile.GetPercentage(cursorPosition)
assert(percentage != -1), "Error: BtrieveFile::GetPercentage():%d:%s.\n" % (rc, btrievePython.Btrieve_StatusCodeToString(btrieveFile.GetLastStatusCode()))
 
 
print ("GetPercentage using Cursor Position:", percentage / 100, "%%")
 
 
numerator = btrieveFile.GetNumerator(btrievePython.Btrieve.INDEX_1, key, numberOfRecords)
assert(numerator != -1), "Error: BtrieveFile::GetNumerator():%d:%s.\n" % (rc, btrievePython.Btrieve_StatusCodeToString(btrieveFile.GetLastStatusCode()))
 
 
print ("GetNumerator using Index:", numerator, "/", numberOfRecords, "key:", keyValue)
 
 
numerator = btrieveFile.GetNumerator(cursorPosition, numberOfRecords)
assert(numerator != -1), "Error: BtrieveFile::GetNumerator():%d:%s.\n" % (rc, btrievePython.Btrieve_StatusCodeToString(btrieveFile.GetLastStatusCode()))
 
 
print ("GetNumerator using Cursor Position:", numerator, "/", numberOfRecords)
 
# Close file.
rc = btrieveClient.FileClose(btrieveFile)
assert(rc == btrievePython.Btrieve.STATUS_CODE_NO_ERROR), "Error: BtrieveClient::FileClose():%d:%s.\n" % (rc, btrievePython.Btrieve_StatusCodeToString(rc))
 
# Delete file.
rc = btrieveClient.FileDelete(btrieveFileName)
assert(rc == btrievePython.Btrieve.STATUS_CODE_NO_ERROR), "Error: BtrieveClient::FileDelete():%d:%s.\n" % (rc, btrievePython.Btrieve_StatusCodeToString(rc))