If an object not belonging to the table depends on the column, CASCADE must be specified, such as foreign key reference and view. The DROP COLUMN form does not physically remove the column, but simply makes it
SQL_ISV_KEY_COLUMN_USAGE = 标识目录中定义的列,这些列被给定用户约束为键。 (中级)SQL_ISV_REFERENTIAL_CONSTRAINTS = 标识给定用户拥有的引用约束。 (中级)SQL_ISV_SCHEMATA = 标识给定用户拥有的架构。 (中级)SQL_ISV_SQL_LANGUAGES = 标识 SQL 实现支持的 SQL 一致性级别、选项和方言。 (中级)SQL_ISV_...
SQLConnect 會建立驅動程式和資料來源的連接。 連接控制碼會參考資料源連線相關資訊的儲存,包括狀態、交易狀態和錯誤資訊。 語法 C++ 複製 SQLRETURN SQLConnect( SQLHDBC ConnectionHandle, SQLCHAR * ServerName, SQLSMALLINT NameLength1, SQLCHAR * UserName, SQLSMALLINT NameLength2, SQLCHAR * Authentication...
CREATETABLEk1(idINTNOTNULL,nameVARCHAR(20),UNIQUEKEY(id))PARTITIONBYKEY()PARTITIONS2; However, if the unique key column were not defined asNOT NULL, then the previous statement would fail. In both of these cases, the partitioning key is theidcolumn, even though it is not shown in the ou...
NO ACTION, which is a standard SQL keyword, is the default in MySQL 8.4. (Also the same as with InnoDB.) In earlier versions of NDB Cluster, when creating a table with foreign key referencing an index in another table, it sometimes appeared possible to create the foreign key even if ...
groupKey * optional Key identifying the group to which the handles should be added. All the handles in the group can later be removed with Accessor.removeHandles(). If no key is provided the handles are added to a default group. classes Inherited Method classes(){String} Inherited fro...
Obtain a SHARE ROW EXCLUSIVE lock on a primary key table when performing a delete operation. DROP TABLE IF EXISTS customer; CREATE TABLE customer AS TABLE customer_address; START TRANSACTION; LOCK TABLE customer IN SHARE ROW EXCLUSIVE MODE; DELETE FROM customer WHERE ca_address_sk IN(SELECT ca...
Starting and Leaving SQLcl Use the following commands to log in to and out of SQLcl. SQLCL [[option] [logon | / NOLOG] [start]] where option has the following syntax: -H[ELP] | -V[ERSION] | [ [-C[OMPATIBILITY] x.y[.z]]] [-L[OGON]] [-NOLOGINTIME] [-R[ESTRICT]...
The syntax for the inner join operation is [ INNER ] JOIN join_association_path_expression [AS] identification_variable For example, the query below joins over the relationship between publishers and magazines. This type of join typically equates to a join over a foreign key relationship in the...
如果连接字符串不包含DSN关键字或找不到数据源,驱动程序管理器将从系统信息中检索与默认数据源关联的驱动程序。 (有关详细信息,请参阅Default Subkey.) 驱动程序管理器将连接字符串中DSN关键字的值更改为“DEFAULT”。 如果连接字符串中的DSN关键字设置为“DEFAULT”,驱动程序管理器将从系统信息中检索与默认数据源...