teradata create table with primary key

Tags: MySQL primary keymysql> show databases;mysql> use INFORMATION_SCHEMA;Mysql> Show tables;Mysql> select * from Key_column_usage; This step is to query the information for each table in each library.Mysql> SELECT * from key_column_usage where table_schema= ' table_name ' and constraint_name= ' PRIMARY '; Query for required tables based on criteriaThis article

. Because the field is to be the primary key for a table, the first condition is to ensure uniqueness in the table. At the same time, combining the characteristics of the SQL Server database itself, you can create a self-adding column for it:

First, let's take a look at what is the primary foreign key?1. Primary key: Uniquely identifies a row in a data table1) There can be only one primary key in a table. If you establish a

There is no self-increment field in Oracle, which can be implemented indirectly via sequence + trigger, Sqlplus login in cmd and run directly. It usually takes a few steps:1 Creating a data sheetCreateTabletest_increase ( useridnumber (10) primarykey, /* primary key, automatically add */ username varchar2 20 ); 2 Creating an auto-grow sequenceCREATESEQUENCE testincrease_sequenceINCREMENTBy1--Add a few e

Tags: IO data for AMP SQL type on OracleSQL Server obtains data types such as column name, column type, column type length, Scale,prec, and so on (Syscolumns,systypes,sysobjects are all views)Select A.name as ColName, b.name as typename,a.length as length,a.scale as scale,a.prec as Prec from syscolumns a,systypes b, sysobjects C where A.xusertype=b.xusertype and a.id=c.id and c.name = ' TableName ' ORDER by c.idOracle obtains data types such as column name, column type, column type length, SCALE

error is that the trigger and DML statements are in the same transaction management, so scenario one is to split the triggers and DML statements into two separate transactions. Pragma autonomous_transaction can be used here; Tells Oracle triggers to be custom transactions. CREATE trigger or replace Tab_b_tri After update on Tab_bFor each rowDeclare--This is the key place to specify custom transactions, whe

public class Jsonresultobject:jsonresult {private Newtonsoft.Json.JsonSerializerSettings Settings { Get Private set; } public Jsonresultobject () {Settings = new Newtonsoft.Json.JsonSerializerSettings {referenceloophandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore} ; public override void Executeresult (ControllerContext context) {if (context = = NULL ) throw new ArgumentNullException ("context"); if (this. Jsonrequestbehavior = = Jsonrequestbehavio

() {} Finnaly { if (rs!=null) Try{rs.close ();} catch (Exception e) {} if (STM ...). If (CN ... ...). } 3. Scrollable cursors pagesize=20; PageNo = 5; CN = NULL stmt = null; rs = null; Try { Sqlserver:sql = "SELECT * from articles"; DataSource ds = new InitialContext (). lookup (Jndiurl); Connection cn = Ds.getconnection (); "SELECT * from user where id=?" --->binary directive PreparedStatement pstmt = cn.preparesatement (sql,resultset.type_scroll_insensitive,...); Depending on the exception

Problem Description: A basic information table, with more than 30 tables in the system, there is a foreign key relationship, when the basic data to delete, you need to determine whether has been used, if used to change the flag bit, if not used to delete directly, how to achieve this process well. It's best to automatically adapt to changes in the table Probl

systypes table, the general user uses the data type to use the Xusertype correspondence is better, does not appear one to many the situation.(c) Syscolumns.length gets the length of the physical memory, so the types of nvarchar and varchar are displayed in the database in half.24.25.4. Get the column names contained in the primary key in the

Label: --Check the foreign key table Nc56.csci there is no corresponding primary key table SELECT A.owner, a.table_name primary_table_name, a.constraint_name Primary_table_key_name, B.owner,

Tags: info create tab creat ONS int const NEW Create1. Create PRIMARY KEY syntaxALTER TABLE table_name ADD CONSTRAINT pk_name PRIMARY KEY (column name);2. Creating FOREIGN

. Because the field is to be the primary key for a table, the first condition is to ensure uniqueness in the table. At the same time, combining the characteristics of the SQL Server database itself, you can create a self-adding column for it:

Tags: Update lots Why code method SOF insert key value InitialInnoDB Index Organization table I. Index organization TABLE definition In the InnoDB storage engine, tables are organized according to the primary key order , which is called the Index Organization

Label:Messages table:Mysql>create Table Messages (->message_id int Auto_increment primary KEY,->user_name varchar () NOT NULL,->author_id int NOT NULL,->body text,->forum_id int not NULL);Forums Table:Mysql>create Table Forums (->

CREATE TABLE day_news (id smallint unsigned auto_increment, title varchar (), content text, author varchar (20 0), Num int unsigned default 0, ntime int unsigned, CNAME varchar (x), hotarticle enum (' Y ', ' n ') default ' n ', Flag enum (' Y ', ' n ') default ' Y ', primary key (ID), Constraint NFK foreign

Label:Typically, after inserting an insert operation on MySQL in the app, we need to get the self-increment primary key for the inserted record. This article describes the 4 ways in which the Java environment obtains the value of the record primary key auto_increment after insert: The InsertRow () method prov

of database is a very broad problem. This paper mainly aims at the present situation of the author's development and Application, and discusses the problems and corresponding solutions to the design of table's primary key when designing the table on MS SQL Server. 2. Primary key