sql create table primary key autoincrement

SQL PRIMARY KEY Instance Tutorial Database PRIMARY KEY constraintThe PRIMARY KEY constraint uniquely identifies each record in a database table.The

@ identity as returnName to the SQL statement to obtain the value of the primary key.Obtain the return value in the program:Copy codeThe Code is as follows:Public int sqlexecutereader (string SQL){DBopen ();SqlCommand myComm = new SqlCommand (SQL, Connection );Int newID = Convert. ToInt32 (myComm. ExecuteScalar ());DB

The primary key is a constraint (constraint), which is attached to an index that can be either a clustered index or a nonclustered index.So there is a primary key on a (or a set) of fields that can only indicate that he has an index on it, but not necessarily a clustered index.For example, the following:1 use [Pratice]

1. Create a new table, set the ID as the primary keyFor example, the table name created is: Uf_receive_pay2. Set the ID of the primary key self-increment, through the sequence implementationCreate sequenceCREATE SEQUENCE Uf_receiv

Tags: mit TCO create SQLite comm ROM creat sql RHCABegin Transaction;Create TABLE MAIN. [temp_970706128] ([Cltcode] varchar (not NULL), [cltname] varchar (50), [pycode] varchar (20), [wbcode] varchar (20), [address] varchar (100), [linkman] varchar (20), [tel] varchar (20), [Memo] Varhcar (50), [State] int,

Tags: OracleYou want to modify the primary key of a table that already has data, and you don't want to affect the original data. Usually there are the following practices1. When the primary key is not namedCREATE TABLE T2 (ID Inte

Generally, the primary key of a table is necessary. A table without a primary key does not comply with the design specifications.Select table_name from user_tables t where not exists(Select table_name from user_constraints c Where

Tags: varchar http date build table data same physical VAR languagePractice: 1. Establish a table relationship: Please create the following table and create the related constraints 1 Usedb1;2 CREATE TABLEClass (3CidINTAuto_incr

Next, in the previous article, the INFORMATION_SCHEMA view is mentioned in the SQL table structure information query including the primary and Foreign keys and self-growth. In fact, in SQL2005, Microsoft has promoted the use of the INFORMATION_SCHEMA System View instead of using sys Dongdong, of course, there is still a lot of information that can only be queried

Label: get table primary key name in PostgreSQL database First, to obtain the primary key information for the teacher table, as follows: SelectPg_constraint.conname asPk_name,pg_attribute.attname asColname,pg_type.typname asTypeN

A problem found during development last week ~~ When nhib.pdf is used, the problem of multiple constraints in a table is stuck for one day, which may be due to poor foundation ~ I am not familiar with the use of the joint primary key and nhib.pdf. It took a day and wasted a day. It is very complicated to use the Union primary