new_city.db 数据库

2018年全国省市区三级联动数据，可直接导入数据库。该数据集涵盖了全国省、地级市、区县三级行政区域划分，确保数据完整性与准确性。此数据可直接应用于各类数据库系统，便于快速部署和使用。适用于企业、政府、教育等多个领域的数据需求。

2019年3月，最新版权威IP地址数据库（www.ip2location.com）发布，提供.csv格式下载，详细记录了各国家、地区及城市级别的IP地址信息，包含[DB3.LITE] IP-COUNTRY-REGION-CITY Database。

Here is the Province, City, County, and Town cascading table and its corresponding data. This structure allows for an organized, hierarchical selection of geographical units starting from the Province down to the Town level, making it easier to navigate and manage regional data.

功能： 在不使用全局变量的情况下，递归搜索指定文件夹下的文件和/或目录。 用法： subdir：返回当前路径下的所有子文件夹。 P = subdir('目录名称')：将给定目录下的所有子文件夹存储到变量 P 中。 [PF] = subdir('目录名称')：将给定目录下的所有子文件夹存储到变量 P 中，并将所有文件名存储到变量 F 中。 使用 sort([F{:}]) 获取所有文件名的排序列表。

DB2是一款功能强大的关系型数据库管理系统。

In Oracle, new plans are not used unless they have been validated. The DBA can validate plans at any time or schedule validation during the maintenance window. The optimizer checks if the new plan is equal to or better than the old one. Statement log and Plan history play key roles in the process. If the new plan is as good as or better than the old one, it is added to the plan baseline. Plans that do not perform as well are stored in plan history and marked as unaccepted. During validation, multiple baselines can be tested and the one with the lowest cost will be chosen. This process is particularly useful for volatile tables and cursor sharing scenarios. By default, the retention period for baselines is 53 weeks.

SQLite数据库不仅可以打开*.db，还可以打开svn数据库。

安装 DB2 数据库

备份数据库分析表和索引有选择性地重组表和索引备份日志清除归档和备份编译无效的过程、试图和函数维护自动运行脚本和调度