Schema models: A collection of database objects.The following are two advanced data types: See the best data engineering & data science books In Python, the dictionary data type stores unordered values like a map for fast look-up and is similar to an unordered list. Unlike other single value element data types, the dictionary data type holds key:value pairs. Online forms might ask us to provide Boolean data, e.g. For example, this post is one large string of characters, with some integers used along the way. We use many of these different data types in our daily lives, often without realising. You can find the Unix timestamp for your date of birth, or any other date, here. This ensures that the timestamp is not affected by time zones and will always be the same regardless of where you are in the world. A Unix timestamp measures the seconds elapsed since that date. ‘Unix epoch’, which happens to be 1st January 1970. Timestamps take many formats, one of the key ones being Unix time which extends from the Times and dates can be stored as a combined value. ![]() The format for time is typically HH:MM:SS. The ISO 8601 syntax will store dates in the YYYY-MM-DD format. If you had to pick your favourite artistic genre here, but picked two, or even all three, then all 3 will be saved in an array. Arrays may have different data structures, since they store multiple values or elements.Īn array for our previous example of artistic genres might include the genres (elements), ‘cubist’, ‘impressionist’ and ‘renaissance’, as well as the indices of each value, so 0, 1, 2, and so on. Arrays store elements in specific orders, usually of all the same type. true or false, but not both).Įxample: The days of the week, or compass directions. The Boolean data is an enumerated type (e.g. So, ‘impressionist’ and ‘cubist’ are the enumerators or elements, then an enumerated type variable may be either ‘impressionist’ or ‘cubist’, but not both. These predefined values are unique and are assigned to a variable. The enumerated data type contains sets of what are known as elements or enumerators. These may be indicated as 0 (false) and 1 (true).Įxample: Does the customer order pizzas? > true/1, does the customer have pineapple on their pizza? > false/0. The Boolean data type is a logical data type that represents values ‘true’ or ‘false’ only. ![]() ![]() ‘39090110011’.Įxample: Strings are sequences of characters. a number ‘+39 090110 011’ and as an integer, or floating-point, e.g. Some values can be stored as both strings, e.g. Strings can include any combination of digits, symbols, spaces, punctuation marks and so on. Strings are sequences of characters, i.e. This entire sentence is constructed from characters, but characters in sequence form a string. a single letter, a symbol, digit, blank space or punctuation mark. Numbers often use both int and float data types.Ĭharacters are singular, e.g. One example of a floating point value is a monetary value. They can however be positive or negative.Īnother numeric data point, but this time for numbers that do have a fractional component. ![]() Integers are a familiar form of numerical data, but crucially, they do not have fractional components.
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