sql server create table primary key autoincrement

think that the tables have clustered indexes and are managed in B-tree mode.If the primary key is not specified as a clustered index, tables may still be managed in a heap mode, resulting in low efficiency.--------------------------------------------------------------------------------Sorting and repeated values:Sorting: multiple fields are specified when a composite index is created. Which field is used f

From: http://www.javaeye.com/topic/215571 In the sqlmap configuration file of ibatisSelectkeyElement hasTypeAttribute, which can be specifiedPreOrPostIndicates that (Pre) Or generate later (Post). Oracle settingsXML Code Id = "insertproduct-Oracle" parameterclass = "com. domain. Product"> Resultclass = "int" keyproperty = "ID" type = "pre"> Ms SQL Server ConfigurationXML Code Id = "inser

Label:The following code has been found on the Internet:DECLARE @Pk varchar (100);Select @Pk =name from sysobjects where parent_obj=object_id (' table name ') and xtype= ' Pk ';If @Pk is not nullBeginEXEC (' Alter table name Drop ' + @Pk)--Delete the primary keyEndThe point here is that the table Sysobjects,sysobjects

index Select * fromMytesttablewhereId='fd3687f4-1' andIntcolumn>0 andParent='F92D6A9D-4E9E-4980-8B46-8AD938CEDCB4' --with index Select * fromMytesttablewhereId='fd3687f4-1' andIntcolumn>0 --with index Select * fromMytesttablewhereParent='F92D6A9D-4E9E-4980-8B46-8AD938CEDCB4' andId='fd3687f4-1' --with index Select * fromMytesttablewhereParent='F92D6A9D-4E9E-4980-8B46-8AD938CEDCB4' andIntcolumn>0 --No index Select * fromMytesttablewhereParent='F92D6A9D-4E9E-4980-8B46-8AD938CEDC

Oracel ALTER TABLE adds a primary key to the table primary key Sql>Sql> CREATE

Recently, I have used the operation of SQL Server database to do something. Well, really long time did not see, to this database is unfamiliar to the pole, even the simplest how to set an ID primary key, let it with the insertion of data, automatic growth ID value settings are forgotten, online check a bit, many people

executes an insert operation to another table with an IDENTITY column, @ @IDENTITY returns the value generated by the trigger. If the trigger inserts a table that does not contain an IDENTITY column, then the @ @IDENTITY will be null. If the insert operation fails, the @ @IDENTITY value will still increase, so the IDENTITY does not guarantee the continuity of the data.@ @IDENTITY is a global variable for t

1, deletion of primary key ALTER TABLE tablename Drop Primary_key executes the above SQL to delete the primary key, and if it is unsuccessful, ALTER TABLE tablename drop CONSTRAINT

How to obtain the primary and foreign key relationships in SQL Server 2008: Select object_name (con. constid) 'relational name ',Object_name (SF. fkeyid) 'Primary key table ',Fcol. Nam

Delete data is constrained when there is a primary foreign key relationship between tables, add, delete failsSolution, we can first set the check of the primary foreign key relationship to shut down → then delete the data → then open the constraintQuery the statement that turns off all foreign

oracle|server| Data | Database because the project needs to convert a database of previous Oracle to SQL Server, the database is migrated using SQL Server DTD today, but after import, only the table structure and data are imported

Tags: style io os ar strong art SP CTI on1. Write scalar value function iconvert2stringCREATE FUNCTION iconvert2string (@N int,@f INT) RETURNS varchar (ten) Asbegindeclare @M intdeclare @L0 intdeclare @CH VARCHAR (10) DECLARE @ST VARCHAR () Select @CH = "Select @ST =convert (VARCHAR), @N) Select @ST =rtrim (@ST) Select @L0 =len (@ST) Select@m=1while (@mDescription: The parameter @f is the length of the variable part after the string. 2. Write a scalar-valued function that returns a

After inserting a record, you want to immediately obtain the primary key return value in the data table. This primary key is automatically generated. In fact, there are many implementation methods, such as performing another query and obtaining it. You can also extract the m

Create a new data table, set Userid as the primary key, and automatically increase Create table T_UserLogin (UserId int not null primary key