sql server auto increment primary key

"sequence" and "Trigger" knowledge. First, create a sequence: Create sequence STU Minvalue 1 Max value 999999999999 Start with 21 Increment by 1 Cache 20; Then, create a trigger for the table student: Create or replace trigger stu_tr Before insert on student For each row Declare -- Local variables here Begin Select stu. nextval into: new. id from dual; End stu_tr; **************************************** **************************************** *****

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

The following article describes how to automatically increase the primary key of a DB2 database, in practice, the DB2 database can use generated always as identity to specify a related field as a self-increasing field, for example: This indicates that id is automatically a self-increasing field, which increases by 1 each time from 1. You can also use generated to calculate the field value through other fiel

After I published the article "Performance Comparison of Self-increment fields and guid field primary keys used in the Database", I got a lot of comments from my friends in the blog Park, we have also proposed some improvement methods for my testing methods. What surprised me was that a garden friend proposed that the test sequence of guid and ID should be reversed and the results should be viewed. Let's te

Generally, when designing the table structure, we set the primary key to auto-increment for the convenience of maintenance (this can be simply set in the sqlserver database, in Oracle, it must be implemented through sequences and triggers). During Development, some data is often used for testing. In this way, the

A very fast problem occurs. In an int auto-increment table, the primary key field is not involved when information is inserted. the following error occurs: violation of primary key constraint 'pk _****'. cannot insert duplicate

There are five types of constraints in SQL Server,Primary key constraints,Foreign key constraints,Unique constraints,Default constraints, and Check constraints, use SQL Server2008 today to demonstrate how these constraints are cre

There are five types of constraints in SQL Server, Primary key constraints, Foreign key constraints, UNIQUE constraints, default constraints, and check constraints, which today use SQL Server2008 to demonstrate the way in which th

in two tables to control the data that can be stored in the foreign key table. In a foreign key reference, a link is created between two tables when one or more of the columns containing the primary key values of one table are referenced by one or more columns in the other table. This column becomes the foreign

Label:When we use SQL server databases , we often create primary keys and indexes , so what is the difference between a primary key and an index? In this paper, we mainly introduce the difference between primary

The InsertRow () method provided by JDBC2.0 The Getgeneratedkeys () method provided by JDBC3.0 Through the SQL Select LAST_INSERT_ID () function Through the SQL @ @IDENTITY variable 1. The InsertRow () method provided by JDBC2.0Since jdbc2.0, this can be done in the following way.[Java]View Plaincopy print? Statement stmt = null; ResultSet rs = null; try { stmt = Conn.createsta

How to Set auto-increment primary keys in oracle First, you must have a table! Create table example (ID Number (4) not null primary key,Name varchar (25 ),Phone varchar (10 ),Address varchar (50 ));If you have any questions about the preceding table creation statements, we r

Document directory SQL Server: For MySQL/SQL Server/Oracle/MS access: For MySQL/SQL Server/Oracle/MS access: MySQL: SQL Server/Oracle

Some people may be confused with primary keys and clustered indexes. In fact, these two concepts are different. The following is a simple description. If you do not want to look at the context text, you can directly look at the comparison between the two. Especially the comparison of the last item. Primary Key) Description from msdn: A table usually has a column

good habit, so it is best to have a and meaningless ID in each of your tables to identify this record.In addition, IDs are not necessarily auto-incrementing and may have different ID generation policies. You do not have to add a primary key. 1. A primary key is not ne

Move from my Netease blog ..... If SQL SERVER creates a primary key when creating a table without a clustered index, the primary key is a clustered index by default for a long time. Ah. In this way, the clustering index becomes t

@elapsedSecond--(1 row (s) affected)--Find data consumption microseconds when indexing the second column--0--(s) affected)--Find the second column of data consumption microseconds after indexing the second column--0As you can see from the execution results, it is very fast to query the second column after the index is indexed.SummarizeIn general, for a table T, a federated primary key (A, a, a, b),

The default auto-Growth of primary keys in Oracle many times when database-related operations are performed, primary keys cannot be filled by users or when multiple users operate on one table at the same time, we need to strictly control the primary key. Here we will focus o

Posted from http://www.sqlservergeeks.com/primary-key-and-unique-key-difference-in-sql-server/Primary and Unique Key both enforce uniqueness of columns on which they is defined. Then wh

Sets whether to use the Getgenereatedkeys method of JDBC to get the primary key and assign a value to the domain model property of the Keyproperty setting. MySQL and SQL Server execute auto-generated key field, so when the databas