我正在使用 MySQLConnector 和 mySQL 将用 Python 编写的工作后端移植到用 C# 编写的 .NET 微服务。我有一个简单的 C# 数据库类，从 Program main 实例化作为第一行之一。它连接到 mysql 服务，然后检查数据库是否存在，并根据需要创建数据库和表，然后用一些种子记录填充它以使其可操作。
我正在尝试通过适当的错误检查和结构来做到这一点，并学习正确的做事方法。
我的问题是：
下面是我当前的课程，然后是我的问题，以及下面的原始工作 Python 数据库模块。任何帮助、提示或技巧表示赞赏。
using System;
using System.Text.RegularExpressions;
using MySqlConnector;
// MySqlConnector notes and refs
// https://mysqlconnector.net/api/mysqlconnector/mysqlerrorcodetype/
// https://dev.mysql.com/doc/mysql-errors/8.0/en/server-error-reference.html
// Adventureworks naming conventions:
// https://stackoverflow.com/questions/3593582/database-naming-conventions-by-microsoft
public class Database
{
static private Database instance;
private bool isReady;
private string dbName;
private string dbUser;
private string dbPassword;
private string dbHost;
private string dbPort;
private string connectionString;
public Database(string dbName, string dbUser, string dbPassword, string dbHost, string dbPort)
{
this.dbName = dbName;
this.dbUser = dbUser;
this.dbPassword = dbPassword;
this.dbHost = dbHost;
this.dbPort = dbPort;
this.connectionString = $"server={dbHost};user={dbUser};port={dbPort};password={dbPassword}";
instance = this;
Initialize();
}
// is this the right approach for various methods in the service to get a connection?
static public MySqlConnection Connect()
{
try
{
var connection = new MySqlConnection(instance.connectionString);
connection.Open();
var command = new MySqlCommand($"USE {instance.dbName}", connection);
command.ExecuteNonQuery();
return connection;
}
catch (MySqlException ex)
{
switch ((MySqlErrorCode)ex.Number)
{
case MySqlErrorCode.AccessDenied:
Console.WriteLine("Access denied: Something is wrong with your user name or password");
break;
case MySqlErrorCode.UnknownDatabase:
Console.WriteLine($"Database {instance.dbName} does not exist");
break;
default:
Console.WriteLine(ex.Message);
break;
}
Environment.Exit(1);
return null; // this line will never be reached, but it's necessary to satisfy the return type of the function.
}
}
static public bool IsReady()
{
return (instance != null && instance.isReady);
}
//*************************************************************************
// Private methods
private async Task Initialize()
{
// create a connection and try to open the DB service
using var connection = new MySqlConnection(connectionString);
try
{
await connection.OpenAsync();
}
catch (MySqlException exConnection)
{
Console.WriteLine(exConnection.Message);
Environment.Exit(1);
}
// service exists, now check if our database exists
try
{
// if it got here, then it found it, need to make it active via USE
using var command = new MySqlCommand($"USE {dbName}", connection);
await command.ExecuteNonQueryAsync();
}
catch (MySqlException exUseDB)
{
if ((MySqlErrorCode)exUseDB.Number == MySqlErrorCode.UnknownDatabase)
{
Console.WriteLine($"Database {dbName} does not exist");
Console.WriteLine($"Creating {dbName}...");
// create the database...
try
{
// load the schema file and run the sql to create the db and tables
string schema = File.ReadAllText("CLIService/SQL/bbe-schema.sql");
string[] sqlCommands = schema.Split(new[] { ";" }, StringSplitOptions.RemoveEmptyEntries);
// create the tables
foreach (string sqlCommand in sqlCommands)
{
string cleanedCommand = Regex.Replace(sqlCommand, "[\n\r]", "");
if (!string.IsNullOrEmpty(cleanedCommand))
{
try
{
var command = new MySqlCommand(cleanedCommand, connection);
await command.ExecuteNonQueryAsync();
}
catch (MySqlException exSqlCommand)
{
Console.WriteLine(exSqlCommand.Message);
Environment.Exit(1);
}
}
}
}
catch (MySqlException exCreateDB)
{
Console.WriteLine($"Failed creating database: {exCreateDB.Message}");
Environment.Exit(1);
}
}
else
{
Console.WriteLine(exUseDB.Message);
Environment.Exit(1);
}
}
// database exists and is used, now populate it if empty
try
{
// there is always 1 admin account created by default, so try to get one record
var command = new MySqlCommand("SELECT * FROM account LIMIT 1", connection);
// should I use ExecuteReaderAsync() instead? If so how?
using (var reader = command.ExecuteReader())
{
// if no records, means it's a new, empty database
if (!reader.HasRows)
{
// load the data file and run the sql to create the table records of initial data
string schema = File.ReadAllText("CLIService/SQL/bbe-data.sql");
string[] sqlCommands = schema.Split(new[] { ";" }, StringSplitOptions.RemoveEmptyEntries);
// create the records
foreach (string sqlCommand in sqlCommands)
{
string cleanedCommand = Regex.Replace(sqlCommand, "[\n\r]", "");
if (!string.IsNullOrEmpty(cleanedCommand))
{
try
{
command = new MySqlCommand(cleanedCommand, connection);
#if USE_ASYNC_AWAIT
// the following line if used it hangs/blocks and never returns
await command.ExecuteNonQueryAsync();
#else
// alternatively the following line returns: "56 Inserted System.Threading.Tasks.Task`1[System.Int32] records"
// but no records are inserted into the DB
var rowCount = command.ExecuteNonQueryAsync();
Console.WriteLine($"Inserted {rowCount} records");
#endif
}
catch (MySqlException exSqlCommand)
{
Console.WriteLine(exSqlCommand.Message);
Environment.Exit(1);
}
}
}
}
}
}
catch (MySqlException exSelectDB)
{
Console.WriteLine($"An error occurred: {exSelectDB.Message}");
}
// database opened, selected and populated
isReady = true;
Console.WriteLine("Database is ready");
}
}
问题：
#if USE_ASYNC_AWAITawait command.ExecuteNonQueryAsync
使用Database类的程序主体：
import mysql
from mysql.connector import errorcode
import re
import os
import tomllib
def connect(config):
# open the database connection
try:
connection = mysql.connector.connect(pool_name="bbepool", **config["DATABASE"]["CONNECTION"])
except mysql.connector.Error as err:
if err.errno == errorcode.ER_ACCESS_DENIED_ERROR:
print("Access denied: Something is wrong with your user name or password")
else:
print(err)
exit(1)
# set the active database
name = config["DATABASE"]["NAME"]
connection.name = name
cursor = connection.cursor()
try:
cursor.execute("USE {}".format(name))
except mysql.connector.Error as err:
print(err)
exit(1)
return connection
def initialize(config):
connection = None
cursor = None
# open the database connection
try:
connection = mysql.connector.connect(**config["DATABASE"]["CONNECTION"])
cursor = connection.cursor()
except mysql.connector.Error as err:
print(err)
exit(1)
# connection successful, check if the db exists already
name = config["DATABASE"]["NAME"]
try:
cursor.execute("USE {}".format(name))
except mysql.connector.Error as err:
print("Database {} does not exist".format(name))
if err.errno == errorcode.ER_BAD_DB_ERROR:
print("Creating {}...".format(name))
try:
cursor.execute("CREATE DATABASE {} DEFAULT CHARACTER SET 'utf8mb4'".format(name))
except mysql.connector.Error as err:
print("Failed creating database: {}".format(err))
exit(1)
print("Database {} created successfully".format(name))
# set the active database
connection.database = name
else:
print(err)
exit(1)
# also set connection to use the new database
config["DATABASE"]["CONNECTION"]["database"] = config["DATABASE"]["NAME"]
# load and run schema
# safe to do as it doesn't create tables if they exist
with open(config["DATABASE"]["SCHEMA"], "rb") as f:
tables = f.read().decode("utf-8").split(";")
for table in tables:
table = re.sub("[\n\r]", "", table)
if len(table) > 0:
try:
cursor.execute(table)
connection.commit()
except mysql.connector.Error as err:
print(err)
exit(1)
# if there is test data
if config["DATABASE"]["DATA"] != "":
# if the db is empty
cursor.execute("SELECT * FROM account LIMIT 1")
# must fetch the data for the cursor
cursor.fetchone()
if cursor.rowcount < 1:
# populate
with open(config["DATABASE"]["DATA"], "rb") as f:
text = f.read().decode("utf-8")
lines = text.split(");\n")
for line in lines:
if len(line) > 0:
try:
cursor.execute(line + ");")
connection.commit()
except mysql.connector.Error as err:
print(err)
exit(1)
# cleanup
cursor.close()
connection.close()
if __name__ == "__main__":
# ensure the current working directory is same as script
os.chdir(os.path.dirname(__file__))
# module vars we use multiple places
config = {}
# In VS Code we can test development or production by setting
# "DEPLOYMENT_ENVIRONMENT": "development", "testing" or "production" in .vscode/launch.json
# but in case the environment variable isn't set, make a default to development
if "DEPLOYMENT_ENVIRONMENT" not in os.environ:
os.environ["DEPLOYMENT_ENVIRONMENT"] = "development"
config_file = "../Settings/config." + os.environ["DEPLOYMENT_ENVIRONMENT"] + ".toml"
with open(config_file, "rb") as f:
config = tomllib.load(f)
# initialize database before switching directories
initialize(config)
处理数据库准备就绪的任何阶段的启动（无服务、服务但无数据库、数据库但无数据）。
using System;
using System.Data;
// https://mysqlconnector.net/tutorials/basic-api/
using MySqlConnector;
using CLIShared;
public class Program
{
static public void Main()
{
string dbName = Environment.GetEnvironmentVariable("DB_NAME");
string dbUser = Environment.GetEnvironmentVariable("DB_USER");
string dbPassword = Environment.GetEnvironmentVariable("DB_PASSWORD");
string dbHost = Environment.GetEnvironmentVariable("DB_HOST");
string dbPort = Environment.GetEnvironmentVariable("DB_PORT");
Database db = new Database(dbName, dbUser, dbPassword, dbHost, dbPort);
// wait for db to be ready
while (Database.IsReady() == false)
{
System.Threading.Thread.Sleep(1000);
}
Console.WriteLine("Database successfully initialized!");
}
}