class Menu :
def __init__ ( self ) :
self.methodList = ( self.createDatabase, self.addRecord, self.deleteRecord,
self.bulkLoad, self.join, self.runQuery, self.report1, self.report2 )
self.env = SliceEnv ()
def getDatabaseServices ( self ) :
choice = self.getMenu ()
while choice != 9 :
self.methodList [choice - 1] ()
i = input ( "Press any key to continue" )
choice = self.getMenu ()
def createDatabase ( self ) :
while True :
try :
tableName = input ( "Enter Table Name: " )
while True :
fieldCount = input ( "Enter the number of columns: " )
try :
fieldCount = int ( fieldCount )
if fieldCount < 1 :
raise ValueError
else :
break
except ValueError as e :
print ( "You have entered a wrong value for number of columns" )
print ( "Please enter a correct value" )
schema = list ()
while fieldCount != 0 :
while True :
try :
columnName = input ( "Enter Column Name: " )
while True :
columnType = input ( "Enter the type for %s column: " % columnName )
if columnType == "STRING" :
schema.append ( SliceField ( columnName, SliceField.STRING ) )
break
elif columnType == "INT" :
schema.append ( SliceField ( columnName, SliceField.INT ) )
break
elif columnType == "FLOAT" :
schema.append ( SliceField ( columnName, SliceField.DOUBLE ) )
break
else :
print ( "You have Entered an incorrect type for %s column" % columnName )
print ( "Please try again" )
break
except Exception as e:
print ( "The following error occurred: %s" %e )
print ( "Please try again" )
fieldCount = fieldCount - 1
indexColumn = input ( "Enter an index column ( or press enter key to skip it) : " )
db = self.env.create ( tableName, schema, indexColumn )
self.env.close ()
break
except Exception as e:
print ( "The following error occurred: %s" %e )
print ( "Please try again" )
print ( "%s database has been created" % tableName )
def addRecord ( self ) :
while True :
try :
dbName = input ( "Enter the name of the database to whom you would like to add record: " )
db = self.env.open ( dbName )
break
except Exception as e :
print ( "The following error occurred: %s" %e )
print ( "Please try again" )
newRecord = db.createRecord ()
#Catch exception
while True :
try :
for column in newRecord.recordSchema :
columnName = column.field[0]
while True :
try :
newData = input ( "Enter a value for %s: " % columnName )
newRecord.set ( columnName, newData )
break
except Exception as e :
print ( "The following error occurred: %s" %e )
print ( "Please try again" )
db.set ( newRecord )
break
except Exception as e :
print ( "The following error occurred: %s" %e )
print ( "Please try again" )
db.commit ()
print ( "A new record have been added to the database named %s" % dbName )
def deleteRecord ( self ) :
while True :
try :
dbName = input ( "Enter the name of the database from whom you would like to delete record: " )
db = self.env.open ( dbName )
break
except Exception as e :
print ( "The following error occurred: %s" %e )
print ( "Please try again" )
if db.index == None :
print ( "%s do not have an index column. Hence, you are not permitted to delete a record from %s" % (dbName,dbName) )
else :
indexColumnName = db.schema[ db.index ][0]
key = input ( "Enter a value for %s to delete the corresponding record: " % indexColumnName )
try :
result = db.delete ( key )
except Exception as e :
print ( "The following error occurred: %s" %e )
return
if result == True :
db.commit ()
print ( "The record with %s having a value of %s has been deleted from %s" % ( indexColumnName, key, dbName ) )
else :
print ( "No record with %s having a value of %s was found in %s" % ( indexColumnName, key, dbName ) )
def bulkLoad ( self ) :
while True :
try :
dbName = input ( "Enter the name of the database into whom you would like to load the data: " )
db = self.env.open ( dbName )
break
except Exception as e :
print ( "The following error occurred: %s" %e )
print ( "Please try again" )
while True :
try :
fileName = input ( "Enter the name of the bulk load file: " )
db.load ( fileName )
break
except Exception as e :
print ( "The following error occurred relating to your bulk load file: %s" %e )
print ( "Please try again" )
print ( "The data has been loaded from %s into %s database" % ( fileName, dbName ) )
def join ( self ) :
while True :
try :
lhsName = input ( "Enter first database name: " )
lhs = self.env.open ( lhsName )
break
except Exception as e :
print ( "The following error occurred: %s" %e )
print ( "Please try again" )
while True :
try :
rhsName = input ( "Enter second database name: " )
rhs = self.env.open ( rhsName )
break
except Exception as e :
print ( "The following error occurred: %s" %e )
print ( "Please try again" )
userInput = input ( "Enter the join column (press enter to perform default join): " )
try :
if userInput == '' :
joinResult = lhs.join ( rhs )
else :
joinResult = lhs.join ( rhs, userInput )
except Exception as e:
print ( "The following error occurred: %s" %e )
return
print ( "Join result is as follows" )
self.printRecords ( joinResult )
def runQuery ( self ) :
while True :
try :
dbName = input ( "Enter the name of the database on which you would like to perform a query: " )
db = self.env.open ( dbName )
break
except Exception as e :
print ( "The following error occurred: %s" %e )
print ( "Please try again" )
resultColumn = list ()
while True :
value = input ( "Enter the name of a column to display" )
if value != '' :
break
print ( "The result of the query must have atleast one column" )
while value != '' :
resultColumn.append ( value )
value = input ( "Enter the name of a column to display (or press enter key if you have entered all the needed columns): " )
operatingColumn = input ( "Enter the name the column to be used for conditional checking records: " )
operator = input ( "Enter the operation you would like to perform: " )
while True :
if operator == "EQ" :
operator = SliceCondition.EQ
break
elif operator == "LT" :
operator = SliceCondition.LT
break
elif operator == "GT" :
operator = SliceCondition.GT
break
else :
print ( "You have entered a wrong operation" )
print ( "Please enter one among EQ, LT and GT operation" )
operator = input ( "Enter the operation you would like to perform: " )
literalValue = input ( "Enter the value you would like compare the %s values against: " % operatingColumn )
condition = SliceCondition ( operatingColumn, operator, literalValue )
query = SliceQuery ( resultColumn, dbName, condition )
try :
queryResult = db.query ( query )
except Exception as e:
print ( "Your query failed due to the following error: %s" %e )
return
self.printRecords ( queryResult )
def printRecords ( self, re ) :
schema = re[0].recordSchema
widthList = list()
for value in schema :
colName, colType = value.field
if colType == SliceField.INT or colType == SliceField.DOUBLE :
widthList.append (7)
print ( "{0:<7}".format ( colName ), end = '' )
else :
widthList.append (35)
print ( "{0:<35}".format ( colName ), end = '' )
print ()
print ( "{0:-<{width}}".format ( '-', width = sum (widthList) ) )
for value in re :
currentRecord = value.record
for i, element in enumerate ( currentRecord ) :
print ( "{0:<{width}}".format ( element, width = widthList[i] ), end = '' )
print ()
def report1 ( self ) :
pass
def report2 ( self ) :
pass
def getMenu ( self ) :
print ()
print ( "Slice database testing menu" )
print ( "1. Create Database" )
print ( "2. Add Record" )
print ( "3. Delete Record" )
print ( "4. Bulk Load" )
print ( "5. Natural Join" )
print ( "6. Run Query" )
print ( "7. Report 1" )
print ( "8. Report 2" )
print ( "9. Exit" )
print ()
while True :
choice = input ( "Enter your choice: ")
try :
choice = int ( choice )
if choice < 1 or choice > 9 :
raise ValueError
break
except ValueError as e :
print ( "You have entered a wrong choice" )
print ( "Please try again" )
print ()
return choice
