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X DevAPI 使用者指南  /  連線與 Session 概念  /  使用 Session 物件

2.3 使用 Session 物件

先前的所有範例都使用了 Session 物件的 getSchema()getDefaultSchema() 方法,這些方法會傳回一個 Schema 物件。您可以使用此 Schema 物件來存取集合和表格。大多數範例都利用 X DevAPI 的能力來串聯所有物件建構,讓您可以在一行中取得 Schema 物件。例如

schema = mysqlx.getSession(...).getSchema();

此物件鏈等同於以下內容,不同之處在於省略了中間步驟

session = mysqlx.getSession(); 
schema = session.getSchema().

不一定要一直串聯呼叫直到取得 Schema 物件,也不一定永遠是您想要的。如果您想要使用 Session 物件,例如,呼叫 Session 物件方法 getSchemas(),則不需要導覽到 Schema。例如

session = mysqlx.getSession(); session.getSchemas().

在此範例中,使用 mysqlx.getSession() 函式來開啟 Session。然後使用 Session.getSchemas() 函式來取得所有可用 Schema 的清單,並將其列印到主控台。

MySQL Shell JavaScript 程式碼

// Connecting to MySQL and working with a Session
var mysqlx = require('mysqlx');

// Connect to a dedicated MySQL server using a connection URI
var mySession = mysqlx.getSession('user:password@localhost');

// Get a list of all available schemas
var schemaList = mySession.getSchemas();

print('Available schemas in this session:\n');

// Loop over all available schemas and print their name
for (index in schemaList) {
  print(schemaList[index].name + '\n');
}

mySession.close();

MySQL Shell Python 程式碼

# Connecting to MySQL and working with a Session
from mysqlsh import mysqlx

# Connect to a dedicated MySQL server using a connection URI
mySession = mysqlx.get_session('user:password@localhost')

# Get a list of all available schemas
schemaList = mySession.get_schemas()

print('Available schemas in this session:\n')

# Loop over all available schemas and print their name
for schema in schemaList:
        print('%s\n' % schema.name)

mySession.close()

Node.js JavaScript 程式碼

// Connecting to MySQL and working with a Session
var mysqlx = require('@mysql/xdevapi');

// Connect to a dedicated MySQL server using a connection URI
mysqlx
  .getSession('user:password@localhost')
  .then(function (mySession) {
    // Get a list of all available schemas
    return mySession.getSchemas();
  })
  .then(function (schemaList) {
    console.log('Available schemas in this session:\n');

    // Loop over all available schemas and print their name
    schemaList.forEach(function (schema) {
      console.log(schema.getName() + '\n');
    });
  });

C# 程式碼

// Connect to a dedicated MySQL server node using a connection URI
var mySession = MySQLX.GetSession("mysqlx://user:password@localhost:33060");

// Get a list of all available schemas
var schemaList = mySession.GetSchemas();

Console.WriteLine("Available schemas in this session:");

// Loop over all available schemas and print their name
foreach (var schema in schemaList)
{
      Console.WriteLine(schema.Name);
}

mySession.Close();

Python 程式碼

# Connector/Python
# Connecting to MySQL and working with a Session
from mysqlsh import mysqlx

# Connect to a dedicated MySQL server using a connection URI
mySession = mysqlx.get_session('user:password@localhost')

# Get a list of all available schemas
schemaList = mySession.get_schemas()

print('Available schemas in this session:\n')

# Loop over all available schemas and print their name
for schema in schemaList:
        print('%s\n' % schema.name)

mySession.close()

Java 程式碼

import java.util.List;
import com.mysql.cj.xdevapi.*;

// Connecting to MySQL and working with a Session
// Connect to a dedicated MySQL server using a connection URI
Session mySession = new SessionFactory().getSession("mysqlx://127.0.0.1:33060/test?user=user&password=password");

// Get a list of all available schemas
List<Schema> schemaList = mySession.getSchemas();

System.out.println("Available schemas in this session:");

// Loop over all available schemas and print their name
for (Schema schema : schemaList) {
System.out.println(schema.getName());
}

mySession.close();

C++ 程式碼

#include <mysqlx/xdevapi.h>

// Connecting to MySQL and working with a Session

// Connect to a dedicated MySQL server using a connection URI
string url = "mysqlx://127.0.0.1:33060/test?user=user&password=password";
{
  Session mySession(url);

  // Get a list of all available schemas
  std::list<Schema> schemaList = mySession.getSchemas();

  cout << "Available schemas in this session:" << endl;

  // Loop over all available schemas and print their name
  for (Schema schema : schemaList) {
    cout << schema.getName() << endl;
  }
}