As with arithmetic operations that are performed on NULL values, when a NULL value is added to a known value the result is typically an unknown value, a string concatenation operation performed with a NULL value, should also produce a NULL result....
1.在sql文件所在目录打开终端(Terminal); 2.使用如下命令登录到sql: mysql -u campus_sec_deal -p 1. 回车后输入用户密码即可进入到mysql交互页面; 3.在终端中输入:source xxx.sql。比如我的sql文件为campus_linux.sql,则可以在终端中输入: source campus_linux.sql 1. 2. 可能的报错 4.当sql脚本中不同...
An operator in a string expression that concatenates two or more character or binary strings, columns, or a combination of strings and column names into one expression (a string operator). Transact-SQL Syntax Conventions Arguments expression Is any validexpressionof any one of the data types in ...
明確解除系結會導致連線維持附加至交易,直到連接關閉或呼叫明確SqlConnection.TransactionEnlist(null)為止。 從 .NET Framework 4 開始,隱含取消系結的變更會過時明確取消系結。 如果InvalidOperationException不是登記的異動或者登記的異動不是使用中狀態,則會擲回Transaction.Current。
System.Data.SqlClient v4.9.0 Source: System.Data.SqlClient.notsupported.cs 获取或设置用于打开 SQL Server 数据库的字符串。 C#复制 publicoverridestringConnectionString {get;set; } 属性值 String 连接字符串,其中包含源数据库名称和建立初始连接所需的其他参数。 默认值为一个空字符串。
If the system ends the transaction (in the scope of a using block) before the last command completes, it will throwInvalidOperationException. Explicit Unbind causes the connection to remain attached to the transaction until the connection is closed or an explicitSqlConnection.TransactionEnlist(null)...
The null elements are also involved in the operation. str1 and str2: required. Values of the STRING type. If the input values are of the BIGINT, DOUBLE, DECIMAL, or DATETIME type, they are implicitly converted into values of the STRING type before calculation. If the input values are ...
<uint32_t zltail> is the offset to the last entry in the list. This allows a pop operation on the far side of the list without the need for full traversal. zltail,记录最后一个entry相对于起始地址的偏移量 <uint16_t zllen> is the number of entries. When there are more than ...
InvalidOperationException 已提交或回滚事务。 或 连接已断开。 注解 Save 方法等效于 Transact-SQL SAVE TRANSACTION 语句。 参数中使用的savePoint值可以是方法的某些实现BeginTransaction的 参数中使用的transactionName值。 保存点提供回滚部分事务的机制。 使用 Save 方法创建保存点,然后调用 Rollback 方法回退...
SqlClientPermission SqlClientPermissionAttribute SqlCommand SqlCommandBuilder SqlConnection SqlConnection 构造函数 属性 AccessToken ClientConnectionId ConnectionString ConnectionTimeout Credential Database DataSource FireInfoMessageEventOnUserErrors PacketSize