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。
SQLite’s DROP TABLE Statement is used to delete the table definition and all related data, indexes, triggers, constraints, and permission specifications for the table.
Be careful when using this command, because once a table is deleted, all information in the table will be lost forever. The basic syntax of the DROP TABLE statement is as follows. You can choose to specify a database name with a table name, as follows: Let’s first confirm that the COMPANY table already exists, and then we delete it from the database. This means that the COMPANY table already exists in the database, so let’s delete it from the database as follows: Now, if you try the .tables command, you will not be able to find the COMPANY table: The display result is empty, which means that the table has been successfully deleted from the database. 1.11.1. Grammar ¶
DROP TABLE database_name.table_name;
1.11.2. Example ¶
sqlite>.tables COMPANY test.COMPANY
sqlite>DROP TABLE COMPANY; sqlite>
sqlite>.tables sqlite>