mysql> create table tb01 (id int,name varchar(10)); ERROR 1146 (42S02): Table 'da01.tb01' doesn't exist

This error occurs when you try to create a table named tb01 in a database named da01, but the database does not exist. You need to create the database first before creating the table.

To create a database, use the following command:

CREATE DATABASE da01;

Then, you can create the table using the following command:

CREATE TABLE tb01 (id INT, name VARCHAR(10));

This will create a table named tb01 with two columns, id and name.

相关问题

mysql> create table tb01; ERROR 1146 (42S02): Table 'da01.tb01' doesn't exist

This error occurs because you are trying to create a table without specifying the columns in it. To create a table, you need to specify the table name and the columns with their data types.

Here's an example of how to create a table named tb01 with two columns, id (integer) and name (varchar):

mysql> CREATE TABLE tb01 (
    -> id INT,
    -> name VARCHAR(50)
    -> );

Once you've created the table, you can start adding data to it using the INSERT INTO statement.

用C++，编写一个简单程序，设计一个建筑物类 Building，由它派生出教学楼类 TeachBuilding 和宿舍楼类 DormBuilding， 前者包括教学楼编号、层数、教室数、总面积等基本信息，后者包括宿舍楼编号、层数、宿舍数、总面积和容纳学生总人数等基本信息。

好的，下面是一个简单的C++程序示例，展示了如何设计这个层次结构：

#include <iostream>
#include <string>

// 定义一个基础的建筑物类 Building
class Building {
public:
    Building(const std::string& id, int floors, double area) : building_id(id), floors(floors), total_area(area) {}
    virtual ~Building() {}

    // 简单的属性获取
    std::string get_building_id() const { return building_id; }
    int get_floors() const { return floors; }
    double get_total_area() const { return total_area; }

protected:
    std::string building_id;
    int floors;
    double total_area;
};

// 派生出教学楼类 TeachBuilding，并添加教室信息
class TeachBuilding : public Building {
private:
    int classrooms;
public:
    TeachBuilding(const std::string& id, int floors, int classrooms, double area)
        : Building(id, floors, area), classrooms(classrooms) {}
    
    // 教室数的获取
    int get_classrooms() const { return classrooms; }
    
    // 打印特定信息
    void print_info() const override {
        std::cout << "Teaching Building ID: " << building_id << ", Floors: " << floors << ", Classrooms: " << classrooms << ", Total Area: " << total_area << std::endl;
    }
};

// 派生出宿舍楼类 DormBuilding，添加宿舍和容纳人数信息
class DormBuilding : public Building {
private:
    int dorms;
    int capacity;
public:
    DormBuilding(const std::string& id, int floors, int dorms, int capacity, double area)
        : Building(id, floors, area), dorms(dorms), capacity(capacity) {}
    
    // 宿舍数和容纳人数的获取
    int get_dorms() const { return dorms; }
    int get_capacity() const { return capacity; }
    
    // 打印特定信息
    void print_info() const override {
        std::cout << "Dormitory Building ID: " << building_id << ", Floors: " << floors << ", Dormitories: " << dorms << ", Capacity: " << capacity << ", Total Area: " << total_area << std::endl;
    }
};

int main() {
    TeachBuilding teach("TB01", 5, 20, 10000);
    teach.print_info();

    DormBuilding dorm("DB01", 4, 15, 900, 8000);
    dorm.print_info();

    return 0;
}

在这个例子中，`Building`是基类，`TeachBuilding`和`DormBuilding`是它的派生类。每个派生类都覆盖了`print_info()`函数，以显示它们特有的信息。