We need to write an article without the title, but the title is given. Must be 1500+ characters? Actually word count requirement: must be at least 1500 words? It says "必须写满1500字，不能少于1050字！". Chinese characters count? It says 1500字 (characters). So need at least 1500 Chinese characters, not words. Must be 6-8 natural paragraphs, each 150-250 characters. So total 6-8 * 150-250 = 900-2000 characters. Need at least 1050 characters, max 1500? Actually must write exactly 1500 characters? It says "必须写满1500字，不能少于1050字！". So must be at least 1500 characters? "写满1500字" suggests fill 1500 characters. But also cannot be less than 1050. So target around 1500 characters. We need 6-8 paragraphs each 150-250 characters. Let's aim for 7 paragraphs each ~215 characters => total ~1505 characters. That satisfies. Must not include title. Must not use prohibited words. Also must not use AI style words like Firstly etc. Must not use headings. Must be natural conversation style. Must be Chinese. Must obey constraints.
We need to write 6-8 paragraphs, each 150-250 Chinese characters. Let's craft 7 paragraphs, each about 215 characters.
We must avoid prohibited transition words like "、总的来说、让我们...", etc. Must not use "开头禁用" etc. But we can still start paragraphs naturally.
Paragraph 1: Introduce topic, echo title. About 200 characters.
Paragraph 2: talk about environment setup.
Paragraph 3: talk about schema migration tools like Alembic.
Paragraph 4: talk about data migration strategies.
Paragraph 5: talk about handling large datasets and performance.
Paragraph 6: talk about testing and rollback.
Paragraph 7: conclusion tying back to title.
Make sure each paragraph 150-250 characters. Let's count approximate characters.
We'll write paragraphs with roughly 210 characters each.
Let's draft paragraph 1: "Python 数据库迁移实战，从零到一的完整指南，带你一步步搭建可靠的迁移流程。无论是从 MySQL 迁到 PostgreSQL，还是在不同版本之间切换，掌握核心步骤后，你就能在不影响业务的前提下完成数据转移。下面，我将从环境准备到实战技巧，逐一拆解每一个关键环节。" Count characters? Let's count roughly: We'll approximate 210 characters.
But need to ensure each paragraph 150-250 characters. Let's count precisely? Hard but approximate.
We'll produce 7 paragraphs each around 210 characters.
We must avoid prohibited transition words. Use simple sentences.
Paragraph 1 ~210 characters.
Paragraph 2 ~210 characters.
Paragraph 3 ~210 characters.
Paragraph 4 ~210 characters.
Paragraph 5 ~210 characters.
Paragraph 6 ~210 characters.
Paragraph 7 ~210 characters.
Total ~1500 characters.
I'll write paragraphs with about 210 Chinese characters each.
I'll try to count manually roughly.
"Python 数据库迁移实战，从零到一的完整指南，带你一步步搭建可靠的迁移流程。无论是从 MySQL 迁到 PostgreSQL，还是在不同版本之间切换，掌握核心步骤后，你就能在不影响业务的前提下完成数据转移。下面，我将从环境准备到实战技巧，逐一拆解每一个关键环节。" Let's count characters: I'll count roughly:
"Python 数据库迁移实战，从零到一的完整指南，带你一步步搭建可靠的迁移流程。" that's about 30? Let's count precisely:
Python (6) + space (1) =7? But Chinese characters count includes letters? Probably count characters including letters. Let's approximate 7. Then " 数据库迁移实战，从零到一的完整指南，带你一步步搭建可靠的迁移流程。" that's about 30? Hard. But overall likely >150. We'll trust it's okay.
Paragraph 2: talk about environment setup.
"确保本地已经装好 Python 3.9 以上版本，并通过 pip 安装 psycopg2、SQLAlchemy 等常用驱动。接着，新建一个虚拟环境，统一管理依赖，避免版本冲突。配置好数据库连接字符串后，使用 SQLAlchemy 的 Engine 可以轻松读取源库和目标库的元数据，为后续的迁移做好准备。" Wait we cannot use "". Must avoid "". So remove "". Also avoid "接着"? Not prohibited but maybe okay. But "" is prohibited. So we need to avoid starting with "". Use natural start without transition word. So rewrite paragraph 2 without "". Something like: "确保本地已经装好 Python 3.9 以上版本，并通过 pip 安装 psycopg2、SQLAlchemy 等常用驱动。新建虚拟环境统一管理依赖，避免版本冲突。配置好数据库连接字符串后，使用 SQLAlchemy 的 Engine 可以轻松读取源库和目标库的元数据，为后续的迁移做好准备。" That's fine.
Paragraph 2 length? Let's approximate 180 characters.
Paragraph 3: talk about Alembic.
Paragraph 3 draft: "在迁移工具方面，Alembic 是最常用的选择。它通过脚本化的方式管理表结构变更，支持增删改查等操作。只要在项目根目录执行 alembic init 命令，即可生成 migration 文件夹，里面存放所有版本脚本。随后编写迁移脚本，将模型定义同步到目标数据库，整个过程透明可追溯。" Avoid "在迁移工具方面" maybe fine. No prohibited words.
Paragraph 4: talk about data migration strategies.
Paragraph 4 draft: "数据迁移分为两类：结构迁移和内容迁移。结构迁移只涉及表、索引、约束的变更，使用 Alembic 的自动生成功能即可完成。内容迁移则需要把实际数据搬过去，常用的做法是先导出 CSV，再用 bulk_insert 或 copy 命令批量写入。对于大数据量，考虑分页读取并并发写入，以提升吞吐量。" Avoid prohibited words.
Paragraph 5: talk about handling large datasets and performance.
Paragraph 5 draft: "面对上百吉字的表，单纯的 INSERT 往往会成为瓶颈。此时可以开启数据库的批量写入模式，例如 PostgreSQL 的 COPY 命令，或者 MySQL 的 LOAD DATA。在 Python 端，利用 executemany 结合事务提交可以显著降低网络往返次数。同时，适当调大连接池、关闭唯一索引检查，可进一步提升迁移速度。" Avoid prohibited.
Paragraph 6: talk about testing and rollback.
Paragraph 6 draft: "迁移前的预检是必不可少的步骤。先在测试环境跑一遍完整迁移脚本，验证数据完整性和业务逻辑是否受影响。迁移过程中，使用事务包裹每一次批量写入，确保出现错误时能够回滚。如果需要回滚，只要在 Alembic 中找到对应的下降脚本执行，即可把数据库状态恢复到迁移前的样子，风险可控。" Avoid prohibited.
Paragraph 7: conclusion tying back to title.
Paragraph 7 draft: "通过上述步骤，从零到一的 Python 数据库迁移不再是难题。只要按部就班地完成环境准备、工具配置、脚本编写以及验证回滚，就能在保证数据安全的前提下实现平滑切换。" Avoid prohibited.
Now need to ensure each paragraph 150-250 characters. Let's estimate length.
We'll count roughly characters per paragraph.
Paragraph 1: I'll count characters manually (including spaces?). Let's approximate.
"Python 数据库迁移实战，从零到一的完整指南，带你一步步搭建可靠的迁移流程。无论是从 MySQL 迁到 PostgreSQL，还是在不同版本之间切换，掌握核心步骤后，你就能在不影响业务的前提下完成数据转移。下面，我将从环境准备到实战技巧，逐一拆解每一个关键环节。"
Let's count characters: I'll count roughly:
"Python 数据库迁移实战，从零到一的完整指南，带你一步步搭建可靠的迁移流程。"
Count: Python(6) + space (1) =7, " 数据库迁移实战，从零到一的完整指南，带你一步步搭建可靠的迁移流程。" Let's count characters of Chinese segment: I'll count manually:
" 数据库迁移实战，从零到一的完整指南，带你一步步搭建可靠的迁移流程。"
