NULL isn't zero or blank: NULL means no entry was made or an explicit NULL was supplied, and it typically implies that the value is either unknown or not applicable. When you use CREATE TABLE or ALTER TABLE to create or alter a table, database and session settings influence and possibly...
mysql>insertintostudentsvalues(1,‘eee’,0); ##插入重复数据失败 ERROR1062(23000): Duplicate entry'1'forkey'idx_st_sid'
There must be a <filespec> entry specifying the primary file. If one or more transaction log files are missing, the log file is rebuilt. The ATTACH_REBUILD_LOG automatically creates a new, 1-MB log file. This file is placed in the default log-file locat...
Partitioned indexes, which consist of partitions containing an entry for each value that appears in the indexed column(s) of the table Function-based indexes, which are based on expressions. They enable you to construct queries that evaluate the value returned by an expression, which in turn ma...
There must be a <filespec> entry specifying the primary file. If one or more transaction log files are missing, the log file is rebuilt. The ATTACH_REBUILD_LOG automatically creates a new, 1-MB log file. This file is placed in the default log-file location. For information about this ...
i am trying to create a table with a single entry called semaphore. The semaphore will contain text indicating which entity currently has control of the db The sql statment is working though: CREATE TABLE semaphoreTable ( semaphore TEXT(50) NOT NULL, ...
the negative number doesn't work in convert()*/if(@precommandisnotnull)exec(@precommand)declare@origdbnvarchar(128)select@origdb=db_name()/*If it's a single user db and there's an entry for it in sysprocesses who isn't us, we can't use it.*//*Create the select*/exec(N'declar...
On entry to the edit procedure, the address for the row description in the parameter list contains a value of zero. VALIDPROC program-name Designates program-name as the validation exit routine for the table. Writing a validation exit routine is described in Validation routines. The ...
Specifies that existing values of special registers are inherited upon entry to the function. STATIC DISPATCH Specifies that the function is dispatched statically. All functions are statically dispatched. FENCEDorNOT FENCED Specifies whether the SQL function runs in an environment that is isolated from ...
(SCHED_NAME,ENTRY_ID)) ENGINE=InnoDB; CREATE TABLE QRTZ_SCHEDULER_STATE ( SCHED_NAME VARCHAR(120) NOT NULL, INSTANCE_NAME VARCHAR(200) NOT NULL, LAST_CHECKIN_TIME BIGINT(13) NOT NULL, CHECKIN_INTERVAL BIGINT(13) NOT NULL, PRIMARY KEY (SCHED_NAME,INSTANCE_NAME)) ENGINE=InnoDB; CREATE...