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。
With You can use the Hypothetical Here is an example that removes a customer with an ID of 7: Now, the If you want to start from Now, there are no records in the SQLite Of DELETE The query is used to delete existing records in the table. You can use the WHERE Of the clause DELETE Query to delete the selected row, otherwise all records will be deleted. 1.19.1. Grammar ¶
WHERE Of the clause DELETE The basic syntax of the query is as follows:DELETE FROM table_name WHERE [condition];
AND Or OR Operator to combine N quantity conditions. 1.19.2. Example ¶
COMPANY The table has the following records:ID NAME AGE ADDRESS SALARY ---------- ---------- ---------- ---------- ---------- 1 Paul 32 California 20000.0 2 Allen 25 Texas 15000.0 3 Teddy 23 Norway 20000.0 4 Mark 25 Rich-Mond 65000.0 5 David 27 Texas 85000.0 6 Kim 22 South-Hall 45000.0 7 James 24 Houston 10000.0
sqlite> DELETE FROM COMPANY WHERE ID = 7;
COMPANY table has the following records:ID NAME AGE ADDRESS SALARY ---------- ---------- ---------- ---------- ---------- 1 Paul 32 California 20000.0 2 Allen 25 Texas 15000.0 3 Teddy 23 Norway 20000.0 4 Mark 25 Rich-Mond 65000.0 5 David 27 Texas 85000.0 6 Kim 22 South-Hall 45000.0
COMPANY If you delete all records from the table, you do not need to use the WHERE Clause, the query DELETE is as follows:sqlite> DELETE FROM COMPANY;
COMPANY table because all records have been passed DELETE Statement is deleted.