3. Mongodb

  • 3.33. MongoDB overlay index query

    The official MongoDB documentation states that the override query is the following query: All query fields are part of t...
    2025-10-25 13:34:20 UTC
  • 3.34. MongoDB query analysis

    MongoDB query analysis can ensure whether the index we have built is valid or not, and it is an important tool for query per...
    2025-10-25 13:34:21 UTC
  • 3.35. MongoDB atomic operation

    Mongodb does not support transactions, so be aware of this when applying it to your project. No matter what the design, do n...
    2025-10-25 13:34:22 UTC
  • 3.36. MongoDB Advanced Index

    Consider the following collection of documents (users): { "address": { "city": "Los Angeles", "state": "California", "pin...
    2025-10-25 13:34:25 UTC
  • 3.37. MongoDB index limit

    3.37.1. Extra expenses ¶ Each index occupies a certain amount of storage space, and it is also necessary to operate o...
    2025-10-25 13:34:20 UTC
  • 3.38. MongoDB ObjectId

    We have used MongoDB’s object Id (ObjectId) in the previous chapters. In this chapter, we will learn about the structure o...
    2025-10-25 13:34:20 UTC
  • 3.39. MongoDB Map Reduce

    Map-Reduce is a computing model that simply breaks down (MAP) a large number of work (data) and then merges the results into...
    2025-10-25 13:34:21 UTC
  • 3.41. MongoDB regular expression

    A regular expression uses a single string to describe and match a series of strings that conform to a syntactic rule. Many...
    2025-10-25 13:34:24 UTC
  • 3.42. MongoDB Management tool: Rockmongo

    RockMongo is a MongoDB management tool written by PHP5. Through Rockmongo you can manage MongoDB services, databases, coll...
    2025-10-25 13:34:22 UTC
  • 3.43. MongoDB GridFS

    GridFS is used to store and restore files (such as pictures, audio, video, etc.) that exceed the 16m (BSON file limit). Gr...
    2025-10-25 13:34:23 UTC
  • 3.44. MongoDB fixed set (Capped Collections)

    MongoDB fixed set (Capped Collections) is a collection with excellent performance and fixed size. For a fixed size, we can i...
    2025-10-25 13:34:21 UTC
  • 3.45. Automatic growth of MongoDB

    MongoDB does not have the same automatic growth function as SQL, and MongoDB’s_ id is the 12-byte unique ID automatically ge...
    2025-10-25 13:34:25 UTC
《地理信息系统原理、技术与方法》  97

最近几年来,地理信息系统无论是在理论上还是应用上都处在一个飞速发展的阶段。 GIS被应用于多个领域的建模和决策支持,如城市管理、区划、环境整治等等,地理信息成为信息时代重要的组成部分之一; “数字地球”概念的提出,更进一步推动了作为其技术支撑的GIS的发展。 与此同时,一些学者致力于相关的理论研究,如空间感知、空间数据误差、空间关系的形式化等等。 这恰好说明了地理信息系统作为应用技术和学科的两个方面,并且这两个方面构成了相互促进的发展过程。