什么是metadata,带例子

metadata is simply data about data,It means it is a description and context of the data. It helps to organize, find and understand data. Here are a few real world examples of metadata.

元数据是数据的数据,这意味着他是数据的描述和上下文。它帮助我们了解和认识数据。下面有一些真是的关于元数据的例子。

Typical metadata

Those are some typical metadata elements:

• Title and description,
• Tags and categories,
• Who created and when,
• Who last modified and when,
• Who can access or update.

A photo

Every time you take a photo with today’s cameras a bunch of metadata is gathered and saved with it

• date and time,
• filename,
• camera settings,
• geolocation.

A book

Each book has a number of standard metadata on the covers and inside. This includes:

• a title,
• author name,
• publisher and copyright details,
• description on a back,
• table of contents,
• index,
• page numbers.

A blog post

Every blog post has standard metadata fields that are usually at before first paragraph. This includes:

• title,
• author,
• published time,
• category,
• tags.

Email

每封邮件都由以下的元数据构成

• 主题
• 由谁发送
• 发送给谁
• 发送时间
• 发送的ip
• 格式

Word document

Every word processing software collects some standard metadata and enables you to add your own fields for each document. Typical fields are:

• title,
• subject,
• author,
• company,
• status,
• creation date and time,
• last modification date and time,
• number of pages.

A spreadsheet

Spreadsheets contain a few metadata fields:

• tab names,
• table names,
• column names,
• user comments.

Relational database

Relational databases (most common type of database) store and provide access not only data but also metadata in a structure called data dictionary or system catalog. It holds information about:

• tables,
• columns,
• data types,
• table relationships,
• and many more

Computer files

All the fields you see by each file in file explorer is actually metadata. The actual data is inside those files. Metadata includes:

• file name,
• type,
• size,
• creation date and time,
• last modification date and time.

Web page

Every web page has a number of metadata fields:

• page title,
• page description,
• icon.

Paper files

Paper document files have often administrative metadata that help manage documents. This might include:

• letter for files organized alphabetically,
• access control information (“classified” for instance),
• logos.

总结

metadata is data about the data

元数据是数据的数据

what is metadata