NOTICE: table "abce" does not exist, skipping DROP TABLE 但是,如果abce是很久以前由另一个数据库schema迁移创建的呢?如果需要在某处执行“撤消”步骤,我们将删除该表。这不是我们所期望的!对于这样的错误事件,我们确实需要在CI测试中报出错误——但是if exists会“掩盖”问题。结果,自动化测试无法捕捉到问题,并...
aligns with the principle of 'Separation of Concerns,'loading the burden of data management onto ...
[id] [int] IDENTITY(1,1) NOT NULL, [name] [varchar](100) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL, [siteCSS] [varchar](100) COLLATE SQL_Latin1_General_CP1_CI_AS NULL, [masterTemplate] [int] NULL, [errorPage] [int] NULL, [homePage] [int] NULL, [addressProduction] [varc...
Here are 4 examples illustrating when you would use IF EXISTS and when you would use IF NOT ...
Opens an SQLite database or creates the database if it does not exist. 参数 filename The filename of the SQLite database. If the file does not exist, SQLite will attempt to create it. PHP must have write permissions to the file if data is inserted, the database schema is modified or...
SQL does not insert a new row if the ID value already exists in the students table. However, SQL inserts a new row with the specified values if the ID value does not exist. Conclusion You learned how to use the INSERT INTO statement with the ON CONFLICT clause to ensure that there are...
[Copy to clipboard]CODE: /**/and/**/(select/**/top/**/1/**/isnull(cast([name]/**/as...
Here are 4 examples illustrating when you would use IF EXISTS and when you would use IF NOT ...
参见 sqlite_popen() - Opens a persistent handle to an SQLite database and create the database if it does not exist sqlite_close() - Closes an open SQLite database sqlite_factory() - Opens a SQLite database and returns a SQLiteDatabase object...
Exist/In 使用 exists表示()内子查询语句返回结果不为空说明where条件成立就会执行主sql语句,如果为空就表示where条件不成立,sql语句就 不会执行。not exists和exists相反,子查询语句结果为空,则表示where条件成立,执行sql语句。负责不执行。 EXISTS里的子查询结果集非空, ...