Oracle 数据库高级操作说明

Oracle 数据库高级操作说明

1. 高级 SQL 操作

1.1 子查询

子查询是嵌套在另一个查询中的查询，常用于复杂的查询场景。

• 单行子查询：

  SELECT first_name, last_name
  FROM employees
  WHERE salary > (SELECT AVG(salary) FROM employees);
  

• 多行子查询：

  SELECT first_name, last_name
  FROM employees
  WHERE department_id IN (SELECT department_id FROM departments WHERE location_id = 1700);
  

1.2 连接查询

• 内连接：

  SELECT e.first_name, e.last_name, d.department_name
  FROM employees e
  INNER JOIN departments d ON e.department_id = d.department_id;
  

• 外连接：

  SELECT e.first_name, e.last_name, d.department_name
  FROM employees e
  LEFT JOIN departments d ON e.department_id = d.department_id;
  

1.3 集合操作

• UNION：

  SELECT first_name FROM employees
  UNION
  SELECT first_name FROM contractors;
  

• INTERSECT：

  SELECT first_name FROM employees
  INTERSECT
  SELECT first_name FROM contractors;
  

• MINUS：

  SELECT first_name FROM employees
  MINUS
  SELECT first_name FROM contractors;
  

2. PL/SQL 编程

2.1 PL/SQL 块

PL/SQL 是 Oracle 的过程化语言扩展，允许在数据库中编写存储过程、函数和触发器。

• 匿名块：

  DECLARE
      v_name VARCHAR2(50);
  BEGIN
      SELECT first_name INTO v_name FROM employees WHERE employee_id = 100;
      DBMS_OUTPUT.PUT_LINE('Employee Name: ' || v_name);
  END;
  

2.2 存储过程

• 创建存储过程：

  CREATE OR REPLACE PROCEDURE get_employee_name (p_employee_id IN NUMBER, p_name OUT VARCHAR2) AS
  BEGIN
      SELECT first_name INTO p_name FROM employees WHERE employee_id = p_employee_id;
  END;
  

• 调用存储过程：

  DECLARE
      v_name VARCHAR2(50);
  BEGIN
      get_employee_name(100, v_name);
      DBMS_OUTPUT.PUT_LINE('Employee Name: ' || v_name);
  END;
  

2.3 函数

• 创建函数：

  CREATE OR REPLACE FUNCTION get_employee_salary (p_employee_id IN NUMBER) RETURN NUMBER AS
      v_salary NUMBER;
  BEGIN
      SELECT salary INTO v_salary FROM employees WHERE employee_id = p_employee_id;
      RETURN v_salary;
  END;
  

• 调用函数：

  SELECT get_employee_salary(100) FROM dual;
  

2.4 触发器

• 创建触发器：

  CREATE OR REPLACE TRIGGER before_employee_insert
  BEFORE INSERT ON employees
  FOR EACH ROW
  BEGIN
      :NEW.hire_date := SYSDATE;
  END;
  

3. 高级备份与恢复

3.1 增量备份

• 增量备份：

  rman target /
  RMAN> BACKUP INCREMENTAL LEVEL 1 DATABASE;
  

3.2 点时间恢复

• 点时间恢复：

  rman target /
  RMAN> RUN {
      SET UNTIL TIME "TO_DATE('2023-10-01 12:00:00', 'YYYY-MM-DD HH24:MI:SS')";
      RESTORE DATABASE;
      RECOVER DATABASE;
  }
  

4. 数据仓库与分区

4.1 数据仓库

• 创建数据仓库表：

  CREATE TABLE sales_fact (
      sale_id NUMBER,
      sale_date DATE,
      product_id NUMBER,
      quantity NUMBER,
      amount NUMBER
  )
  PARTITION BY RANGE (sale_date) (
      PARTITION p1 VALUES LESS THAN (TO_DATE('2023-01-01', 'YYYY-MM-DD')),
      PARTITION p2 VALUES LESS THAN (TO_DATE('2024-01-01', 'YYYY-MM-DD'))
  );
  

4.2 分区表维护

• 添加分区：

  ALTER TABLE sales_fact ADD PARTITION p3 VALUES LESS THAN (TO_DATE('2025-01-01', 'YYYY-MM-DD'));
  

• 合并分区：

  ALTER TABLE sales_fact MERGE PARTITIONS p1, p2 INTO PARTITION p1_p2;
  

5. 高级性能优化

5.1 索引优化

• 创建位图索引：

  CREATE BITMAP INDEX idx_employee_gender ON employees(gender);
  

• 创建函数索引：

  CREATE INDEX idx_employee_upper_name ON employees(UPPER(last_name));
  

5.2 并行查询

• 启用并行查询：

  ALTER SESSION ENABLE PARALLEL DML;
  SELECT /*+ PARALLEL(employees, 4) */ * FROM employees;
  

5.3 物化视图

• 创建物化视图：

  CREATE MATERIALIZED VIEW mv_employee_salary
  AS
  SELECT department_id, AVG(salary) avg_salary
  FROM employees
  GROUP BY department_id;
  

• 刷新物化视图：

  EXEC DBMS_MVIEW.REFRESH('mv_employee_salary');
  

6. 高级安全管理

6.1 数据加密

• 透明数据加密 (TDE)：

  ALTER TABLE employees MODIFY (salary ENCRYPT);
  

6.2 虚拟私有数据库 (VPD)

• 创建 VPD 策略：

  BEGIN
      DBMS_RLS.ADD_POLICY(
          object_schema => 'hr',
          object_name => 'employees',
          policy_name => 'emp_policy',
          function_schema => 'hr',
          policy_function => 'emp_policy_func',
          statement_types => 'SELECT, INSERT, UPDATE, DELETE'
      );
  END;
  

6.3 审计增强

• 细粒度审计：

  BEGIN
      DBMS_FGA.ADD_POLICY(
          object_schema => 'hr',
          object_name => 'employees',
          policy_name => 'audit_emp_salary',
          audit_condition => 'salary > 10000',
          audit_column => 'salary'
      );
  END;
  

7. 高级监控与诊断

7.1 AWR 报告

• 生成 AWR 报告：

  @?/rdbms/admin/awrrpt.sql
  

7.2 ADDM 报告

• 生成 ADDM 报告：

  @?/rdbms/admin/addmrpt.sql
  

7.3 SQL 调优顾问

• 使用 SQL 调优顾问：

  DECLARE
      task_name VARCHAR2(30);
  BEGIN
      task_name := DBMS_SQLTUNE.CREATE_TUNING_TASK(sql_id => 'abc123');
      DBMS_SQLTUNE.EXECUTE_TUNING_TASK(task_name);
  END;
  

8. 结论

通过掌握这些高级操作，您可以更有效地管理和优化 Oracle 数据库，满足复杂的企业级应用需求。无论是复杂的 SQL 查询、PL/SQL 编程、高级备份与恢复，还是性能优化和安全管理，Oracle 提供了丰富的工具和功能来支持您的数据库管理工作。