null test

1 Static voidMain (string[] args)2 {3 //cannot start with \ or return null4RegistryKey RK = Registry.CurrentUser.OpenSubKey (@"\software");5Console.WriteLine (RK = =NULL);//true6 7RK = Registry.CurrentUser.OpenSubKey

Create Table Table1 (ID varchar2 (10) Not null, grzhye number (10, 2), gmsfhm varchar2 (18), rylb varchar2 (10), cardno varchar2 (20 )); comment on column table1.id is 'personal number'; Comment on column table1.grzhye is 'personal account balance ';

Recently done cache lab used the getopt function, with man 3 getopt view the following usage, make a summary. Description: The Getopt function is used to parse command-line arguments, with an option element of '-' or '-' that starts with a '-' or '-

When using WindowsProgramI believe no users like to see the sudden program crash! To avoid program crashes, it is best for programmers to use an exception processor to ensure a friendly user experience when writing programs that are prone to errors.

Released on: 4/28/2004 | updated on: 4/28/2004 C # The Working Group and members of the C # community are answering frequently asked questions (FAQ) via web logs at http://blogs.msdn.com/csharpfaq. All entries in the site will be displayed to msdn

Abnormal system:----------| Throwable the superclass of an exception or error class--------------| Error error errors are generally used for JVM or hardware-initiated problems, so we do not normally use code to handle errors.--------------|

How to use Java code to obtain the encoding method of a file, file stream, or string Today, I learned how to use Java code to obtain the encoding method of files, file streams, or strings through network resources. I will share the Code with

Efficient data structures in Android developmentAndroid development, in JAVA2EE or Android common data structure has map,list,set, but Android as a mobile platform, some API (many are efficiency issues) is obviously not ideal, in the spirit of

Analysis of Different errors in MySQL table sorting rules and mysql table sorting rules MySQL multi-table join reports an error: [Err] 1267-Illegal mix of collations (utf8_general_ci, IMPLICIT) and (utf8_unicode_ci, IMPLICIT) for operation '= That

How to use Java code to obtain the encoding method of files, file streams, or strings, and java Encoding Today, I learned how to use Java code to obtain the encoding method of files, file streams, or strings through network resources. I will share

In Android development, the efficient data structure replaces HashMap with SparseArray, and sparsearrayhashmap #### Efficient data structure in Android Development In android development, data structures commonly used in java2ee or android include

[Email protected] ~]# mysql-uroot-pzaq12wsx #入库mysql> show databases; #查库ERROR 2006 (HY000): MySQL server has gone awayNo connection. Trying to reconnect ...Connection id:24Current database: * * * NONE * * *+--------------------+| Database |+--------

MySQL Stored procedure features1, use temporary table, dynamic cursor can only use temporary table2, the temporary table has more than one field, the cursor has multiple parameters to accept3. Cyclic reading and writing data4, if there is a record

Today, I used Entity Framework to rewrite an earlier project. When it involved processing null values, I encountered a problem: how to query records with a null field in the database, I wrote several examples for testing and then used SQL Server

PostgreSQL solves the tinyint data type problem in a system database, creating the data types that you need:CREATE DOMAIN tinyintAs smallintCONSTRAINT tinyint_check Check (value >= 0 and value ALTER DOMAIN tinyintOWNER to Postgres;COMMENT on DOMAIN

1. class defines public class company {private string name; Private Employee managingdirector; public string Name {get {return this.name;} Set {this.name = value;} Public Employee managingdirector {get {return

Recursionselect is an extremely convenient extension method, which requires only a fewCodeThis extension method is frequently used in my code. This is an example I have provided before: [Testmethod] public void testmethod13 () {// obtain the

question: Please implement a function to determine whether a binary tree is symmetrical. If a binary tree is the same as its mirror image, then it is symmetrical. Detailed design code is as follows: BOOL Issymmetrical (binarytreenode* pRoot1,

Summarize the MySQL table of use case execution.DELIMITER $$ Use' test_cases ' $$DROP PROCEDURE IF EXISTS' P_write_report_3 ' $$CREATEDefiner=' Root ' @ ' localhost 'PROCEDURE' P_write_report_3 ' (inchP_table_nameVARCHAR(

database table has not null,default,check,unique,primary key,foreign KEY six kinds of constraints.A, NOT NULL----non-null constraintNULL indicates no data and does not represent a specific numeric value, so null in the database is not equal to NULL.