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5. Postgresql

  • 5.34. PostgreSQL index

    Index is a special table query that accelerates search engines to retrieve data. Simply put, an index is a pointer to the da...
    2025-10-25 13:32:25 UTC

  • 5.35. PostgreSQL ALTER TABLE command

    In PostgreSQL ALTER TABLE The command is used to add, modify, and delete a column that already exists in a table. Beside...
    2025-10-25 13:32:23 UTC

  • 5.36. PostgreSQL TRUNCATE TABLE

    In PostgreSQL TRUNCATE TABLE Used to delete the data of the table, but not the table structure. It can also be used ...
    2025-10-25 13:32:23 UTC

  • 5.37. PostgreSQL View (View)

    The View (view) is a fake table, just a PostgreSQL statement stored in the database by the associated name. A View is actu...
    2025-10-25 13:32:27 UTC

  • 5.38. PostgreSQL TRANSACTION (transaction)

    TRANSACTION (transaction) is a logical unit in the execution process of database management system, which is composed of a l...
    2025-10-25 13:32:25 UTC

  • 5.39. PostgreSQL LOCK (lock)

    The main purpose of locking is to maintain the consistency of database data, which can prevent users from modifying a row or...
    2025-10-25 13:32:24 UTC

  • 5.40. PostgreSQL subquery

    Subquery, or internal query, or nested query, refers to embedding query statements in the WHERE clause of a PostgreSQL query...
    2025-10-25 13:32:24 UTC

  • 5.41. PostgreSQL AUTO INCREMENT (automatic growth)

    AUTO INCREMENT (automatic growth) generates a unique number when a new record is inserted into the table. PostgreSQL uses ...
    2025-10-25 13:32:24 UTC

  • 5.42. PostgreSQL PRIVILEGES (permission)

    Whenever a database object is created, it is assigned an owner, usually the person who executes the create statement. For ...
    2025-10-25 13:32:27 UTC

  • 5.43. PostgreSQL time / date functions and operators

    5.43.1. Date / time operator ¶ The following table shows the behavior of basic arithmetic operators (+, * , etc.)...
    2025-10-25 13:32:22 UTC

  • 5.44. Common functions of PostgreSQL

    PostgreSQL built-in functions, also known as aggregate functions, are used to perform processing on string or numeric data. ...
    2025-10-25 13:32:26 UTC

Web框架

 942

Principles and Applications of WebGIS

 37

WEB基础

 287

Principles, Technologies, and Methods of Geographic Information Systems

 102

In recent years, Geographic Information Systems (GIS) have undergone rapid development in both theoretical and practical dimensions. GIS has been widely applied for modeling and decision-making support across various fields such as urban management, regional planning, and environmental remediation, establishing geographic information as a vital component of the information era. The introduction of the “Digital Earth” concept has further accelerated the advancement of GIS, which serves as its technical foundation. Concurrently, scholars have been dedicated to theoretical research in areas like spatial cognition, spatial data uncertainty, and the formalization of spatial relationships. This reflects the dual nature of GIS as both an applied technology and an academic discipline, with the two aspects forming a mutually reinforcing cycle of progress.