XML
XML (eXtensible Markup Language) is a widely used markup language designed to store, transport, and organize data in a structured, hierarchical format. It is both human-readable and machine-readable, making it ideal for data exchange between systems, especially over the web.
Many computer systems contain data in incompatible formats. Exchanging data between incompatible systems (or upgraded systems) is a time-consuming task for web developers. Large amounts of data must be converted, and incompatible data is often lost. XML stores data in plain text format. This provides a software- and hardware-independent way of storing, transporting, and sharing data. XML also makes it easier to expand or upgrade to new operating systems, new applications, or new browsers, without losing data. With XML, data can be available to all kinds of "reading machines" like people, computers, voice machines, news feeds, etc.
Key Features of XML:
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Self-Descriptive: XML tags define the data, making it easy to understand what the data represents. For example:
- Hierarchical Structure: Data is organized in a tree-like structure with elements nested within each other.
- Customizable Tags: Unlike HTML, XML does not have predefined tags; users can create their own to suit their needs.
- Platform-Independent: XML can be used across various platforms and programming languages.
- Extensible: Since XML is not bound to any specific set of tags or rules, it can be extended to meet the needs of different applications.
- Unicode Support: XML supports Unicode, enabling it to handle multiple languages.
Common Use Cases
- Data Exchange: For transferring data between systems or applications (e.g., SOAP, REST APIs).
- Configuration Files: Used in software applications (e.g., .xml files for app settings).
- Web Services: In protocols like RSS and Atom feeds.
- Document Markup: For structuring documents like XHTML.
Advantages:
- Easy to understand and maintain.
- Well-supported by many tools and libraries.
- Can validate data structure using schemas like DTD (Document Type Definition) or XSD (XML Schema Definition).
Disadvantages:
- Verbose: Can lead to large file sizes.
- Slower to parse compared to some alternatives like JSON.
