db2 not null

Understand the principle of null in depth and the principle of null in Depth -- Null principle -- oracle always treats null and null strings ''with the same length as 0. For example, ''is null is true,'' =

Tags: DB2 replica environment variables"Progressive DB2.DBA system Management, operation and application Case" (New) Reading notes 5DB2 multi-copy installation and default replica switching impact on environment variablesIn this blog post, I have documented in detail the process of installing a DB2 copy with a wizard on windowsxp. It then discusses the nature of

When a field in the database is set to Null, the mobile phone will return Null by default. if I want the mobile phone to return Null, I have to make a judgment. 1. if I want to leave the returned result blank on the mobile phone, I will not make any judgment. how should I set the table field default? 2. set the default value of the table field to

For beginners of SQL, the concept of null values often creates confusion, and they often assume that null is the same thing as a MySQL empty string. This is not the case. For example, the following statement is completely different:mysql> INSERT into my_table (phone) VALUES (NULL); The code is as follows Copy Code Mysql> INSERT into m

Tags: Execute SQL last unknown should be keyword AST this different select "SQL Server": SQL Server considers null to be minimal. In ascending order : Null values are ranked first in the default. To arrange the back, then: the order by case if Col is null then 1 else 0 end, col descending : null values default to the l

Label:Believe that a lot of people who have been using MySQL for a long time, the concept of these two field properties is not very clear, the general will have the following questions: My field type is not NULL, why can I insert a null value is less efficient than null for a gross NOT NULL When judgi

1, Introduction--From the wiki interpretation/dev/null:In a Unix-like system, a/dev/null, or empty device, is a special device file that discards everything written to it (but reports a successful write operation) and reads it immediately to get an EOF.In programmer jargon, especially in Unix jargon,/dev/null is called a bit bucket or black hole. Empty devices are often used to discard unwanted output strea

Differences between null and not null in mysql and efficiency issues Mysql users may encounter the following situations: 1. My field type is not null. Why can I insert null values? 2. Why is not null more efficient than null? 3. W

In the process of DB2 development, one of the most important tasks throughout the development process is the maintenance of the database, which is necessary to maintain a large information system; Leave a simple maintenance manual for a rainy year; The following parts of the maintenance order are collected to treat our maintenance engineers and project managers. * update:2006-06-14 * Memo: Please use "

At work we are constantly writing code, writing JavaScript, very little time for conceptual research. I have nothing to do today, I studied the relationship between "null" and "0". I hope you have seen the end of the harvest. Alert (null>=0) What does the above code pop up? False? True? is actually true. So why is it? Why is "Null>=0" true? When

21. check the local node db2 list node direcotry 22. node deserialization db2 uncatalog node node_name www.2cto.com 23. database cataloguing db2 catalog db db_name as db_alias at node node_name 24. view the database catalog db2 list db directory 25. connect to the database db2