If you don't set the option to allow null values, the column remains blank, but the user isn't able to save the row until they supply a value for the column. Limitations Before you begin, be aware of the following limitations and restrictions: ...
Set Default value for column 'd_mediumint' in table 'datatype1' Column 'd_int' in table 'datatype1' have no comments. Set unsigned attribute on auto increment column in table 'datatype1'. Column 'd_bigint' in table 'datatype1' have no comments. Set Default value for column 'd_big...
Sparse columns reduce the space requirements for null values at the cost of more overhead to retrieve nonnull values. A wide table has defined a column set, which is an untyped XML representation that combines all the sparse columns of a table into a structured output. The number of indexes...
若要定义列集,请在 *<column_set_name>* FOR ALL_SPARSE_COLUMNS 或ALTER TABLE 语句中使用 关键字。列集的使用准则使用列集时,请考虑以下准则:稀疏列和列集可以作为同一语句的一部分添加。 如果某个表已包含稀疏列,则不能向该表中添加列集。 无法更改或重命名列集列。 若要更改列集,必须删除稀疏列和列...
SQLColumns returns the list of column names in specified tables. The driver returns this information as a result set on the specified StatementHandle.SyntaxC++ Copy SQLRETURN SQLColumns( SQLHSTMT StatementHandle, SQLCHAR * CatalogName, SQLSMALLINT NameLength1, SQLCHAR * SchemaName, SQLSMALLINT...
column of theuniqueidentifierdata type that has the ROWGUIDCOL attribute. This column must not allow null values and must have either a UNIQUE or PRIMARY KEY single-column constraint. TheGUIDvalue for the column is supplied by the application when data is being inserted, or by a DEFAULT ...
字段的值只能在给定范围中选择,如单选框,多选框 enum 单选 只能在给定的范围内选一个值,如性别 sex 男male/女female set 多选 在给定的范围内可以选择一个或一个以上的值(爱好1,爱好2,爱好3...) 代码语言:javascript 复制 枚举类型(enum) An ENUM column can have a maximum of 65,535 distinct elements...
ADD CONSTRAINT DF_Users_Status DEFAULT 'Active' FOR Status; 1. 2. 错误日志代码块(带高亮注释) -- 错误1: Cannot insert the value NULL into column 'Status', table 'Users';-- column does not allow nulls. INSERT fails.-- 这通常是由于缺少约束导致的。
SQL0798N 無法指定值給定義為 GENERATED ALWAYS 的直欄 column-name。 解說 當在表格中插入或更新橫列時,指定了一個值給 GENERATED ALWAYS 直欄 column-name。除非指定了關鍵字 DEFAULT,否則不應在 INSERT 的直欄清單或更新的 SET 子句中指定 GENERATED ALWAYS 直欄。 未執行 INSERT 或 UPDATE。 使用者回應...
set, is_rollover, is_shutdown, is_default, buffer_count, buffer_size, last_event_time, event_count, trace_event_id, trace_event_name, trace_column_id, trace_column_name, expensive_eventFROM(SELECTt.idAStrace_id, row_number()over(PARTITIONBYt.idorderbyte.trace_event_id, tc.trace_column...