CREATE VIEW emp_regions_view AS SELECT (e.emp_name,e.emp_id,r.objectid,r.rname,r.region) FROM employees e, regions r WHERE e.emp_id = r.emp_id; 授予视图权限 您可将视图权限授予特定用户,而无需授予这些用户对基表(employees 和 regions)的访问权限。在本例中,将两个...
1、E = 外部表（由许多外部数据包装器之一提供）2、I = 索引3、m = 物化视图4、s = 序列5、t = 表格6、v = 视图postgres=# \dt List of relations Schema | Name | Type | Owner---+---+---+--- public | example_tbl | table | postgres 4、显示角色和成员 角色用于连接到 ...
Create a view to restrict access In this example, user rocket creates a view (view_dept_201) on the employees table to restrict access to only those rows where the department is 201: psqltestdbrocketEnterpasswordforuserrocket:CREATEVIEWview_dept_201ASSELECTemp_id,name,hire_...
postgres=# \password dlf // 重新设置用户dlf的密码,然后需要 \q退出后才生效 c:\>psql exampledb < user.sql // 将user.sql文件导入到exampled数据库中 postgres=# \h select // 精细显示SQL命令中的select命令的使用方法 postgres=# \l // 显示所有数据库 postgres=# \dt // 显示当前数据库中的所有...
An example: GET DIAGNOSTICS integer_var = ROW_COUNT; The second method to determine the effects of a command is to check the special variable named FOUND, which is of type boolean. FOUND starts out false within each PL/pgSQLfunction call. It is set by each of the following types of sta...
class ExampleView(APIView): throttle_classes = (UserRateThrottle,) def get(self, request, format=None): content = { 'status': 'request was permitted' } return Response(content) 7 ORM和非ORM数据资源的序列化 序列化和反序列化是一个web框架的基础功能,但要做到易用也是不容易的,django rest ...
For example: Sql>select * from dept; DEPTNO DNAME LOC --- --- --- 10 ACCOUNTING NEW YORK sql>col LOC heading location sql>select * from dept; DEPTNO DNAME location --- --- --- 10 ACCOUNTING NEW YORK 2). 将列名ENAME改为新列名EMPLOYEE NAME并将新列名放在两行上: Sql>select * from...
CREATE TABLE users ( id SERIAL PRIMARY KEY, name VARCHAR(100), email VARCHAR(100) UNIQUE ); 对比:MySQL使用AUTO_INCREMENT,而PostgreSQL使用SERIAL来自动生成主键。 3. 插入数据 MySQL INSERT INTO users (name, email) VALUES ('Alice', 'alice@example.com'); ...
数据插入Example 1. explain analyze insert into tb_auth_detail( "person_id", "dept_id", "dev_id", "door_id", "auth_status", "finger_status", "face_status", "del_card_number", "auth_person_schedule_id", "auth_dept_schedule_id", ...
View Code 以上两种方式都会有问题 我们可以在某个操作出错后加入事务提交或者回滚 View Code 4、数据库清理 4.1 日常清理(VACUUM;) 日常清理(VACUUM;),因为有大量的更新(update)"删除(delete)操作,会有大量的空间需要释放。 每日执行一次VACUUM,每周访问量低的时候执行VACUUM FULL; ...