-- 创建表CREATE TABLE employees (
    employee_id NUMBER PRIMARY KEY,
    first_name VARCHAR2(50),
    last_name VARCHAR2(50),
    email VARCHAR2(100),
    hire_date DATE,
    salary NUMBER(8,2));-- 插入数据INSERT INTO employees VALUES (1, '张', '明', 'zhang.ming@company.com', DATE'2020-01-15', 8000);-- 查询数据SELECT * FROM employees WHERE salary > 5000;-- 创建索引CREATE INDEX idx_employee_name ON employees(last_name, first_name);

// 插入文档db.employees.insertOne({
  employee_id: 1,
  personal_info: {
    first_name: "张",
    last_name: "明",
    contact: {
      email: "zhang.ming@company.com",
      phone: "+86-13800138000"
    }
  },
  employment_details: {
    hire_date: new Date("2020-01-15"),
    salary: 8000,
    department: "技术部"
  },
  skills: ["Java", "Python", "MongoDB"]});// 查询文档db.employees.find({"employment_details.salary": {$gt: 5000}});// 创建索引db.employees.createIndex({"personal_info.last_name": 1});

-- Oracle事务示例BEGIN
  UPDATE accounts SET balance = balance - 1000 WHERE account_id = 123;
  UPDATE accounts SET balance = balance + 1000 WHERE account_id = 456;
  INSERT INTO transaction_log VALUES (transaction_seq.NEXTVAL, SYSDATE, '转账', 1000);
  COMMIT;EXCEPTION  WHEN OTHERS THEN
    ROLLBACK;
    RAISE;END;

// MongoDB事务示例const session = db.getMongo().startSession();session.startTransaction();try {
  db.accounts.updateOne(
    {account_id: 123},
    {$inc: {balance: -1000}},
    {session}
  );
  db.accounts.updateOne(
    {account_id: 456},
    {$inc: {balance: 1000}},
    {session}
  );
  db.transaction_log.insertOne({
    timestamp: new Date(),
    type: "转账",
    amount: 1000
  }, {session});
  session.commitTransaction();} catch (error) {
  session.abortTransaction();
  throw error;}

// 启用分片sh.enableSharding("company_db");// 创建分片集合sh.shardCollection("company_db.employees", 
  {"employee_id": "hashed"});// 添加分片服务器sh.addShard("shard1/mongodb1:27017");sh.addShard("shard2/mongodb2:27017");

-- Oracle RAC配置示例CREATE CLUSTER employee_cluster (employee_id NUMBER)SIZE 512 HASHEYS 100;CREATE TABLE employees_clustered
CLUSTER employee_cluster (employee_id)AS SELECT * FROM employees;

-- 多对多关系建模CREATE TABLE projects (
    project_id NUMBER PRIMARY KEY,
    project_name VARCHAR2(100));CREATE TABLE employee_projects (
    employee_id NUMBER REFERENCES employees(employee_id),
    project_id NUMBER REFERENCES projects(project_id),
    role VARCHAR2(50),
    PRIMARY KEY (employee_id, project_id));-- 复杂查询SELECT e.first_name, e.last_name, p.project_name, ep.roleFROM employees eJOIN employee_projects ep ON e.employee_id = ep.employee_idJOIN projects p ON ep.project_id = p.project_id;

// 嵌入文档方式db.employees.insertOne({
  employee_id: 2,
  name: "李伟",
  projects: [
    {
      project_id: 1,
      project_name: "电商平台开发",
      role: "后端开发",
      start_date: new Date("2023-01-01"),
      end_date: new Date("2023-06-30")
    }
  ]});// 引用方式db.projects.insertOne({
  project_id: 1,
  project_name: "电商平台开发",
  team_members: [
    {
      employee_id: 2,
      role: "后端开发",
      allocation: 0.8
    }
  ]});

-- Oracle运维常用命令-- 查看表空间使用情况SELECT tablespace_name, 
       round(SUM(bytes) / 1024 / 1024, 2) total_mb,
       round(SUM(bytes - blocks * 8192) / 1024 / 1024, 2) free_mbFROM dba_free_spaceGROUP BY tablespace_name;-- 监控性能SELECT sql_text, executions, elapsed_time, cpu_timeFROM v$sqlORDER BY elapsed_time DESC;

// MongoDB运维命令// 查看数据库状态db.stats()// 监控慢查询db.setProfilingLevel(1, 100)  // 记录超过100ms的查询// 查看集合状态db.employees.stats()// 性能分析db.employees.find().explain("executionStats")

// Oracle表结构/*
CREATE TABLE customers (
    customer_id NUMBER PRIMARY KEY,
    name VARCHAR2(100),
    address VARCHAR2(200),
    city VARCHAR2(50),
    country VARCHAR2(50)
);
*/// MongoDB文档结构db.customers.insertOne({
  customer_id: 1001,
  name: "北京某科技有限公司",
  addresses: [
    {
      type: "办公地址",
      street: "海淀区中关村大街",
      city: "北京",
      country: "中国",
      is_primary: true
    }
  ],
  contacts: [
    {
      name: "张经理",
      phone: "+86-13800138000",
      email: "zhang@company.com"
    }
  ]});