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。
You can use the DELETE statement to delete the data in the PostgreSQL table. The following is the general syntax for DELETE statements to delete data: If not specified In general, we need to Create the COMPANY table ( 下载 COMPANY SQL 文件 ), the data are as follows: The following The results are as follows: As can be seen from the above results, the data with an id of 2 has been deleted. The following statement deletes the entire COMPANY table: 5.20.1. Grammar ¶
DELETE FROM table_name WHERE [condition];
WHERE Clause, all records in the PostgreSQL table will be deleted. WHERE Clause to delete the corresponding record, and the conditional statement can use the AND or OR operator to specify one or more. 5.20.2. Example ¶
runoobdb# select * from COMPANY; id | name | age | address | salary ----+-------+-----+-----------+-------- 1 | Paul | 32 | California| 20000 2 | Allen | 25 | Texas | 15000 3 | Teddy | 23 | Norway | 20000 4 | Mark | 25 | Rich-Mond | 65000 5 | David | 27 | Texas | 85000 6 | Kim | 22 | South-Hall| 45000 7 | James | 24 | Houston | 10000 (7 rows)
SQL Statement deletes data with an ID of 2:runoobdb=# DELETE FROM COMPANY WHERE ID = 2;
id | name | age | address | salary ----+-------+-----+-------------+-------- 1 | Paul | 32 | California | 20000 3 | Teddy | 23 | Norway | 20000 4 | Mark | 25 | Rich-Mond | 65000 5 | David | 27 | Texas | 85000 6 | Kim | 22 | South-Hall | 45000 7 | James | 24 | Houston | 10000 (6 rows)
DELETE FROM COMPANY;