1. Sqlite

  • SQLite is a software library that implements a self-sufficient, serverless, zero-configuration, tra...
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  • This tutorial helps you understand what SQLite is, how it differs from SQL, why it is needed, and how its application ...
    2025-10-25 12:31:13 UTC
  • An important feature of SQLite is zero configuration, which means that there is no need for complex installation or ma...
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  • This chapter will show you the simple but useful commands used by SQLite programmers. These commands are called SQLite...
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  • SQLite follows a unique set of rules and guidelines called grammar. This tutorial lists all the basic SQLite syntax an...
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  • The SQLite data type is a property that specifies the data type of any object. Every column, variable, and expression ...
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  • SQLite’s sqlite3 Command is used to create a new SQLite database. You do not need any special permissio...
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  • Suppose that when multiple databases are available at the same time, you want to use any of them. SQLite’s ATT...
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  • SQLite’s DETACH DATABASE Statement is used to separate and detach a named database from a database conn...
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  • SQLite’s CREATE TABLE Statement is used to create a new table in any given database. Creating a basic t...
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  • SQLite’s DROP TABLE Statement is used to delete the table definition and all related data, indexes, tri...
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  • SQLite’s INSERT INTO Statement is used to add a new data row to a table in the database. ...
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  • SQLite’s SELECT Statement is used to get data from an SQLite database table and return it as a result t...
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  • 1.14.1. What is the SQLite operator? ¶ Operator is a reserved word or c...
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  • Expressions are those of one or more values, operators, and calculated values SQL A combinat...
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  • SQLite’s WHERE Clause is used to specify the conditions for getting data from one or more tables. ...
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  • SQLite Of AND And OR Operator is used to compile multiple conditi...
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  • SQLite Of UPDATE The query is used to modify existing records in the table. You ...
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  • SQLite Of DELETE The query is used to delete existing records in the table. You ...
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  • SQLite Of LIKE Operator is a text value that matches the pattern specified by a ...
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  • SQLite’s GLOB Operator is a text value that matches the pattern specified by a wildcard. If the search ...
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  • SQLite’s LIMIT Clause is used to restrict the value of the SELECT The amount ...
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  • SQLite’s ORDER BY Clause is used to sort data in ascending or descending order based on one or more col...
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  • SQLite’s GROUP BY Clause is used with SELECT Statement to group the same data...
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  • HAVING Clause allows you to specify conditions to filter the grouped results that will appear i...
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  • SQLite’s DISTINCT Keywords vs. SELECT Statement to eliminate all duplicate re...
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  • SQLite’s PRAGMA The command is a special command that can be used to control various environment variab...
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  • Constraints are rules that are enforced on the data columns of a table. These are used to limit the types of data that...
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  • SQLite’s Join Clause is used to combine records of tables in two or more databases. JOIN ...
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  • SQLite’s UNION Clause / operator is used to merge two or more SELECT Statemen...
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  • SQLite’s NULL Is an item used to represent a missing value. One of the tables NULL ...
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  • You can temporarily rename the table or column to another name, which is called 别名 . The use of a table...
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  • SQLite 触发器(Trigger) Is a callback function for the database that is automatically executed / called whe...
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  • A Transaction is a unit of work that performs work on a database. A Transaction is a unit or sequence of work that is ...
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  • Index is a special look-up table, which is used by database search engine to speed up data retrieval. Simply put, an i...
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  • The “INDEXED BY index-name” clause states that a named index is required to find the values in the previous table. ...
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  • SQLite’s ALTER TABLE The command does not modify an existing table by performing a complete dump and re...
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  • In SQLite, there is no TRUNCATE TABLE Command, but you can use the ...
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  • A View is nothing more than a SQLite statement stored in the database by the associated name. A View is actually a com...
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  • Subqueries, or internal queries, or nested queries, refer to the SQLite In the query ...
    2025-10-25 12:31:16 UTC

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.