266 lines
7.7 KiB
Python
266 lines
7.7 KiB
Python
#!/usr/bin/env python3
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"""
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MySQL 8 -> MySQL 5.7 数据库迁移脚本
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依赖: pip install pymysql
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使用方法:
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python py/migrate_mysql8_to_mysql57.py
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功能:
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1. 从源 MySQL 8 读取表结构，修正 collation 后在目标 MySQL 5.7 建表
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2. 逐表批量拷贝数据
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3. 修正 auto-increment 值
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注意:
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- 目标库应为空库（无同名表）
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- 运行前请确保源库和目标库都可连接
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"""
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from __future__ import annotations
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import re
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import sys
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from typing import Any
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import pymysql
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import pymysql.cursors
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# ============================================================
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# 硬编码数据库配置
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# ============================================================
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SOURCE_CONFIG = {
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"host": "127.0.0.1",
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"port": 3306,
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"user": "root",
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"password": "PLEASE_CHANGE_ME",
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"database": "meshtastic",
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"charset": "utf8mb4",
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}
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TARGET_CONFIG = {
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"host": "127.0.0.1",
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"port": 3307,
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"user": "root",
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"password": "PLEASE_CHANGE_ME",
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"database": "meshtastic",
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"charset": "utf8mb4",
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}
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BATCH_SIZE = 5000
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# ============================================================
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# 工具函数
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# ============================================================
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def _conn(config: dict[str, Any]) -> pymysql.Connection:
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"""创建数据库连接，使用 DictCursor 方便按列名访问"""
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return pymysql.connect(
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host=config["host"],
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port=config["port"],
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user=config["user"],
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password=config["password"],
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database=config["database"],
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charset=config["charset"],
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cursorclass=pymysql.cursors.DictCursor,
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)
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def fix_collation(ddl: str) -> str:
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"""将 MySQL 8 默认 collation 替换为 MySQL 5.7 兼容版本"""
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ddl = ddl.replace("utf8mb4_0900_ai_ci", "utf8mb4_general_ci")
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ddl = ddl.replace("utf8mb4_0900_as_ci", "utf8mb4_general_ci")
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return ddl
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def get_all_tables(conn: pymysql.Connection) -> list[str]:
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with conn.cursor() as cur:
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cur.execute("SHOW TABLES")
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key = list(cur.description[0])[0]
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return [row[key] for row in cur.fetchall()]
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def get_table_columns(conn: pymysql.Connection, table: str) -> list[str]:
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"""返回表的所有列名（按顺序）"""
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with conn.cursor() as cur:
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cur.execute("SHOW COLUMNS FROM `%s`" % table)
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return [row["Field"] for row in cur.fetchall()]
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def get_auto_increment(
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conn: pymysql.Connection, table: str
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) -> int | None:
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"""获取某张表当前的 AUTO_INCREMENT 值"""
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with conn.cursor() as cur:
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cur.execute(
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"SELECT AUTO_INCREMENT FROM information_schema.TABLES "
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"WHERE TABLE_SCHEMA = DATABASE() AND TABLE_NAME = %s",
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(table,),
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)
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row = cur.fetchone()
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if row and row["AUTO_INCREMENT"]:
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return int(row["AUTO_INCREMENT"])
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return None
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def row_count(conn: pymysql.Connection, table: str) -> int:
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with conn.cursor() as cur:
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cur.execute("SELECT COUNT(*) AS cnt FROM `%s`" % table)
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return cur.fetchone()["cnt"]
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# ============================================================
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# 主流程
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# ============================================================
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def migrate() -> int:
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src = _conn(SOURCE_CONFIG)
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tgt = _conn(TARGET_CONFIG)
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print(f"[连接] 源 MySQL 8 @ {SOURCE_CONFIG['host']}:{SOURCE_CONFIG['port']}")
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print(f"[连接] 目标 MySQL 5.7 @ {TARGET_CONFIG['host']}:{TARGET_CONFIG['port']}")
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print()
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# 1. 在目标库建库（如还不存在）
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try:
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with tgt.cursor() as cur:
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cur.execute(
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"CREATE DATABASE IF NOT EXISTS `%s` "
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"CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci"
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% TARGET_CONFIG["database"]
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)
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cur.execute("USE `%s`" % TARGET_CONFIG["database"])
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tgt.select_db(TARGET_CONFIG["database"])
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except Exception as e:
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print(f"[错误] 创建目标数据库失败: {e}")
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return 1
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tables = get_all_tables(src)
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print(f"[发现] 源库共 {len(tables)} 张表: {', '.join(tables)}")
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print()
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# 2. 逐表建表（修正 collation）
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print("=" * 60)
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print("阶段 1: 在目标库创建表结构")
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print("=" * 60)
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for idx, table in enumerate(tables, 1):
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with src.cursor() as cur:
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cur.execute("SHOW CREATE TABLE `%s`" % table)
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row = cur.fetchone()
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ddl = row["Create Table"]
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ddl = fix_collation(ddl)
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try:
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with tgt.cursor() as cur:
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cur.execute(ddl)
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tgt.commit()
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print(f" [{idx:2d}/{len(tables)}] OK `{table}`")
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except Exception as e:
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print(f" [{idx:2d}/{len(tables)}] 错误 `{table}`: {e}")
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tgt.rollback()
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return 1
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print()
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# 3. 逐表拷贝数据
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print("=" * 60)
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print("阶段 2: 拷贝表数据")
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print("=" * 60)
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total_rows_copied = 0
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auto_increments: dict[str, int | None] = {}
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for idx, table in enumerate(tables, 1):
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columns = get_table_columns(src, table)
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if not columns:
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auto_increments[table] = None
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print(f" [{idx:2d}/{len(tables)}] SKIP `{table}` (0 列)")
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continue
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col_quoted = ", ".join("`%s`" % c for c in columns)
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placeholders = ", ".join(["%s"] * len(columns))
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insert_sql = "INSERT INTO `%s` (%s) VALUES (%s)" % (
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table,
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col_quoted,
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placeholders,
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)
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table_count = 0
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with src.cursor() as read_cur:
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read_cur.execute("SELECT * FROM `%s`" % table)
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batch = read_cur.fetchmany(BATCH_SIZE)
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while batch:
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rows_values = [
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[row.get(c) for c in columns] for row in batch
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]
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try:
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with tgt.cursor() as write_cur:
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write_cur.executemany(insert_sql, rows_values)
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tgt.commit()
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table_count += len(rows_values)
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print(
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f"\r [{idx:2d}/{len(tables)}] `{table}` -> {table_count} 行",
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end="",
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flush=True,
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)
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except Exception as e:
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print()
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print(f" [{idx:2d}/{len(tables)}] 错误 `{table}`: {e}")
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tgt.rollback()
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return 1
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batch = read_cur.fetchmany(BATCH_SIZE)
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# 修正 auto_increment
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ai = get_auto_increment(src, table)
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auto_increments[table] = ai
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if ai is not None:
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with tgt.cursor() as cur:
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cur.execute(
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"ALTER TABLE `%s` AUTO_INCREMENT = %s" % (table, ai)
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)
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tgt.commit()
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total_rows_copied += table_count
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print(
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f"\r [{idx:2d}/{len(tables)}] `{table}` -> {table_count} 行 [OK]"
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)
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# 4. 验证
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print()
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print("=" * 60)
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print("阶段 3: 验证行数")
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print("=" * 60)
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all_match = True
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src_total = 0
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tgt_total = 0
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for table in tables:
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s = row_count(src, table)
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t = row_count(tgt, table)
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src_total += s
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tgt_total += t
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status = "OK" if s == t else "不匹配!"
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if s != t:
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all_match = False
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print(f" `{table}`: 源={s} 目标={t} [{status}]")
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print()
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print(f" 总计: 源={src_total} 目标={tgt_total}")
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src.close()
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tgt.close()
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if all_match:
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print()
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print("迁移完成，所有表行数一致。")
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return 0
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else:
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print()
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print("警告: 部分表行数不一致，请检查。")
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return 1
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if __name__ == "__main__":
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sys.exit(migrate())
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