123 lines
4.3 KiB
Python
123 lines
4.3 KiB
Python
# Nick Alvarez, CS 657, PA3, Spring 21
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# Python 3.7+ required.
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# Utility file for table queries
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import os
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import dbutils
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# Select *
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def queryAll(UserQuery, workingDB):
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selLower = dbutils.inputCleaner("SELECT * FROM ", UserQuery)
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selection = dbutils.inputCleaner("select * from ", selLower)
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if workingDB != None:
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if dbutils.tableExistenceCheck(selection, workingDB):
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f = open(f'{workingDB}/{selection}.txt', 'r')
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print(f.read())
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f.close()
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else:
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print(f"Could not query table {selection} because it does not exist.")
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else:
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print("Please specify which database to use.")
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# Select (with variables)
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def querySpecific(UserQuery, workingDB):
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selLower = dbutils.inputCleaner("SELECT ", UserQuery)
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selection = dbutils.inputCleaner("select ", selLower)
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# Gathering list of variables
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selectColumns = selection.replace(",", "").split()
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selectColumns = selectColumns[:selectColumns.index("from")]
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# Table name
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tName = selection.split()[len(selectColumns)+1]
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# Gathering what to filter by
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whereColumn = selection.split()[len(selectColumns)+3]
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whereRecord = selection.split()[len(selectColumns)+5]
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operand = dbutils.getOperand(selection.split()[len(selectColumns)+4])
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if workingDB != None:
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if dbutils.tableExistenceCheck(tName, workingDB):
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f = open(f'{workingDB}/{tName}.txt', 'r')
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tempFile = f.readlines()
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f.close()
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selectColumnNums = []
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columnNameString = ""
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listToReturn = []
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count = 0
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for line in tempFile:
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if (count == 0): # Headers
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# Finding the indexes of select and where columns
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columnList = line.split()
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columnListWithTypes = columnList.copy()
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del columnListWithTypes[2::3]
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del columnList[1::3]
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columnCount = 0
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# If variable is found in table, record its index
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for word in columnList:
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if word in selectColumns:
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selectColumnNums.append(columnCount)
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if (word == whereColumn):
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whereColumnNum = columnCount
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columnCount += 1
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# Creating a custom table header for the selected columns
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for index in selectColumnNums:
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columnNameString += f"{columnListWithTypes[index]} {columnListWithTypes[index+1]} | "
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queryHeader = columnNameString[:-3]
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listToReturn.append(queryHeader)
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if (count > 0): # Values
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tupleDetails = line.split()
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# Determines what to do with each row
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def querySpecificHelper():
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# Creates the row output
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def queryStringMaker():
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queryString = ""
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for index in selectColumnNums:
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queryString += f"{tupleDetails[index]} | "
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queryResult = queryString[:-3]
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listToReturn.append(queryResult)
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if (operand == 0): # Equality
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# The type checking here handles strings and numbers separately
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# Ex. 150 or 150.00 would not find 150.00 or 150, respectively
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if (type(tupleDetails[whereColumnNum]) is str):
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if (tupleDetails[whereColumnNum] == whereRecord):
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queryStringMaker()
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elif (type(tupleDetails[whereColumnNum]) is not str):
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if (float(tupleDetails[whereColumnNum]) == float(whereRecord)):
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queryStringMaker()
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elif (operand == 1): # Greater than
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if (float(tupleDetails[whereColumnNum]) > float(whereRecord)):
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queryStringMaker()
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elif (operand == -1): # Less than
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if (float(tupleDetails[whereColumnNum]) < float(whereRecord)):
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queryStringMaker()
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elif (operand == -3): # Inequality
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if (type(tupleDetails[whereColumnNum]) is str):
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if (tupleDetails[whereColumnNum] != whereRecord):
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queryStringMaker()
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elif (type(tupleDetails[whereColumnNum]) is not str):
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if (float(tupleDetails[whereColumnNum]) != float(whereRecord)):
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queryStringMaker()
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querySpecificHelper()
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count += 1
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for line in listToReturn: # Prints table
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print(line)
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else:
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print(f"Could not query table {tName} because it does not exist.")
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else:
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print("Please specify which database to use.") |