Tuesday, August 23, 2016

Oracle database vs MongoDB


Oracle Database:

Oracle uses structured query language for database access.It will store data in tables.
It follows predefined schema and set up rules to govern the relationships.

MongoDB Database:

MongoDB stores data as JSON format. All the related information is stored together for faster data access.
At any time, you can change the structure of records by adding new fields.
It is a database which designed for big data storage and query.
It can gain its performance mainly by key value based design and easy to scale out
To achieve the performance and scalability, MongoDB ditches the transaction support.
We cannot use for transaction related applications like Payment gateway etc.

Both Oracle and MongoDB have a rich query language.
MongoDB is not meant to replace the relational databases.It simply fullfills the different needs.

Monday, August 8, 2016

QR Code Maximum payload/data

 Maximum data qr code can store depends on the following factors.Data type,Number of pixels and error correction level.

 Numeric only - Maximum 7,089 characters (0,1,2...9)

 Alpha Numeric - Maximum 4,296 characters (0–9, A–Z [upper-case only], space, $, %, *, +, -, ., /, :)

 Binary/byte   - Maximum 2,953 characters.

Tuesday, August 2, 2016

Operators in Swift

Operators:
An Operator a special symbol that tells the compiler to perform mathematical or logical operations.

Assignment Operator:

The assignment operator (a=b) initailizes or updates the vlaue of a with a vlue of b.

let b = 12
var a = 10
a = b  // a is now 12

Arithmetic Operators :


Swift supports 4 arithmetic operators.

Addition
Subtraction
Multiplication
Division

Remainder Operator :

9 % 4 = 1

5 % 1.5 = 0.5



Comparison Operator :

Equal to (a == b)
Not equal to (a != b)
Greater than (a > b)
less than (a < b)   .................etc

Ternary Conditional Operator :

Ternary conditional operator is a special operator with 3 parts.

question ? answer 1 : answer 2

if question {
answer 1
} else {
answer2
}


if question is true, it evaluates answer 1, otherwise, it evaluates answer 2.

Range Operators:

Closed Range Operator:

The closed range operator (a...b) defines a range from a to b,incluses vlues a and b.

ex:

  for index in 1...6 {
 
  print("\(index) times 6 is \(index * 5)")
  }
 
  // 1 times 5 is 5
  // 2 times 5 is 10
  // 3 times 5 is 15
  // 4 times 5 is 20
  // 5 times 5 is 25
 
  Half- Open range operator :
 
  The half open range operator (a..<b) defines a range from a to b, but does not include b.

let countrynames = ["India","Malaysia","USA","Singapore","Thailand"]

 let count =  countrynames.count

 for i in 0..<count {
print("Country \(i+1) is called \(countrynames[i])")
}
// Country 1 is called India
// Country 2 is called Malaysia
.
//// Country 5 is called Thailand


Logical Operators :
Logical operators are similar to c, java languages.
Logical NOT (!a)
Logical AND (a && b)

Logical OR (a || b)

Swift Basics

Swift is an Open Source, powerful language for mac OS, iOS.
Swift 3 is the major release developed at Swift.org.


Declaring Constants :

let maximumMembers = 5
var minimumMembers = 2
let pi = 3.1416

Type Annotations :

var username: String
username = "Srinivas Nidadavolu"
println(username) // prints Srinivas Nidadavolu

Constant value cannot be changed.

var username = "SRINIVAS NIDADAVOLU"
username = "KARUNA" // compile time error - username cannot be changed

Comments :

Comments in swift is similar to other programming languages like java, javascipt and c etc.

// for comment

/* this is also a comment*/

Semicolons:
Swift doesnt need a semicolon (;) after every statement. Its optional. If your using multiple statements in the same line, then its required.

Data Types :

32 Bit and 64 bit platforms :

32 bit platform:

Int is Int32
UInt is UInt32

64 bit platform:

Int is Int64
UInt is UInt64

Booleans:

let userActive = true

if userActive{
println("user is active")
}else{
println("user is inactive")
}

Optionals:
Swift handles the absence value with Optionals.


var userStr = String? = nil



import Cocoa

var userStr : String?=nil

if  userStr!=nil {
println(userStr)
}else{
println("It contains nil")

}

Saturday, July 30, 2016

Push notifications - GCM- MismatchSenderId

{ multicast_id: 7577665675695298000,
  success: 0,
  failure: 1,
  canonical_ids: 0,

  results: [ { error: 'MismatchSenderId' } ] }


{ multicast_id: 7058249237348086000,
  success: 0,
  failure: 1,
  canonical_ids: 0,

  results: [ { error: 'InvalidRegistration' } ] }

Saturday, July 23, 2016

Sunday, May 29, 2016

Friday, May 27, 2016

Saturday, May 21, 2016


Transport Security has blocked a cleartext HTTP (http://) resource load since it is insecure. Temporary exceptions can be configured via your app's Info.plist file