db2 not null

PHP is a loosely typed programming language, and it is an indispensable step in a function to examine the "type" of the passed parameter value and whether the value is null or NULL. Type check Starting with PHP5, PHP allows type constraints on the parameters of a function, that is, the type of the parameter can be constrained to an object, an interface, an array (starting with PHP 5.1), or cal

In mysql, null, not null, default, and auto_increment are common content. Here I will detail the usage of null, not null, default, and auto_increment in msyql. NULL and not null modifiers: You can add the

Mysql explores not null constraints and null values, and mysqlnull Yesterday, a front-end developer suddenly asked me a basic question: "My table columns have the not null constraint. Why can I insert null values? What's more strange is that you can insert null values before

In MySQL, each field definition contains additional constraints or modifiers that can be used to increase the constraints on the input data. Today, let's take a look at MySQL field constraints:NULLAndNot NULLmodifiers,DEFAULTModifier,auto_incrementModifier.null and NOT NULL modifiers: You can add this null or NOT NULL modifier after each field to specify whether

In sqlserver 2000, the null value of datetime is the default value 00:00:00. in C #, the null value of datetime is the minimum value 0001-01-01 00:00:00. For database insertion, the date value updated to a null value is somewhat less than expected. For example, I inserted a null value. I also took out a

I encountered a strange problem in a project, and it took me a lot of time to solve it. The final debugging found that it was a judgment problem-about 0 and ''(null single quotes, for better understanding, I added a space), I found that 0 = "was actually true, depressed at the same time decided to write a simple page test, swear to 0, null, empty, the relationship between

I. Wild pointer The "wild pointer" is not a NULL pointer, but a pointer to the "junk" memory. There are two main causes of "wild pointer: (1) pointer variables are not initialized. When a pointer variable is created, it does not automatically become a NULL pointer. Its default value is random, which means it is random. Therefore, the pointer variable should be initialized at the same time when it is created

between midnight and arg. Monthname (arg): returns the month name of arg. Dayname (arg): returns the week of arg. Common examples: Returns the current system time. Oracle:selectsysdatefromdual; DB2:　selectcurrentdatefromsysibm.sysdummy1 Returns the next day of the current time) Oracle:selectsysdate,sysdate+interval'1'day　fromdual; DB2:　selectcurrentdate+1dayfromsysibm.sysdummy1 3.

In javascript, what are the differences between Null and Null strings? Let me introduce how to judge the differences between Null and Null strings. Recently, I suddenly found that my JavaScript code is bloated, so I began to study the simplified JavaScript method. In this way, we can make our JavaScript code look fresh

What are the values of null and non-null when creating a table in mysql? What are the values of null and non-null when creating a table in mysql? Mysql ------ solution -------------------- I usually try not to use null. if your 0 and nul