what is difference between megabytes and gigabytes

), Managed in a constrained form. But at the same time, it automatically creates a unique nonclustered index, with the performance and some functionality of the index. In fact, unique key constraints are constrained by unique indexes. A unique index is an index that uniquely checks a field and can set various parameters for flexibility. So when we create the uniqueness of a column, which is better to use?

What is the difference between a magnetic stripe card and a chip card? The central bank announced that the magnetic stripe card will be full chip card, chip card in the end what is the good? What

performance, stability, and functionality, and can achieve millions data storage. MySQL and web servers can be put together initially, but when the traffic reaches a certain scale, the MySQL database should be isolated from the Web server and run on a separate server while maintaining a stable connection between the Web server and the MySQL server.When database traffic reaches a higher level, consider using a solution such as a DB cluster such as MySQL Cluster or a library table hash.Overall, t

Question one: The difference between statement and PreparedStatementFirst of all, what is statement in Java:statement is an important way for Java to perform database operations to send SQL statements to the database, based on the database connection that has been established . Specific steps:1. First import java.sql.*

Tags: the comparison between make STR is SQL info strong. comNote: M here is not a specific length stored in the database, it was always mistaken for int (3) to store only 3-length numbers, and int (11) would store 11-length numbers, which is a big mistake. In fact, when we choose the type of int, whether it is int (3

What the hell is a closure? Before JS inside heard some, but the actual development how do not feel how to use this concept? Just recently when learning laraval, found that the routing configuration is the closure function (the tutorial said that), do not understand what this closure means? I see the code and JS inside

A Hungry man type: public class singleton{ private static Singleton Singleton = new Singleton (); Private Singleton () {} public static Singleton getinstance () {return singletion;} } Lazy Type: public class singleton{ private static Singleton Singleton = null; public static synchronized synchronized getinstance () { if (singleton==null) { Singleton = new Singleton (); } return singleton; } } Comparison: The A Hungry man is thread-safe, creating a

this issue, this post is very good (fgetc and getc, which fast?) )。 OK, the above is the difference between fgetc and getc! However, it is important to add that the two functions are the same in GNU C, they are all implemented by functions, and then getc simply and rudely add a macro declaration

What is the difference between a H67 motherboard and a H77 motherboard? As shown below: H67 and H77 The difference is big, I want to buy a can use Ivy Bridge processor motherboard, is going to buy a new i5 3550 of the processor,

PS: What is the difference between the mask and the channel? Here we can use the concept of the mask to help understand the meaning of the channel, the usual masking can be seen as this: when you select a portion of the image on the PS image using the selection tool, the gray-black part of the selection is the mask,

"Netizen asks a question": have been not clear exactly what difference does photoelectric converter, fiber transceiver, light cat, light module have? "Answer": Optical module is inserted in the router or switch, can not be used independently, belong to other devices part. and netizens mentioned (photoelectric converter, optical transceiver, light cat, optical m

Color difference component input is a way to display signal input using color difference component port. Color Difference Port At present, in some professional video workstation/editing card professional-grade video equipment or high-end DVD players and other appliances on the see there are YUV, YcbCr, y/b-y/b

What does an OEM mean OEM Full name Original equipment manufacturer, refers to the manufacturer according to the original requirements and authorization, according to specific conditions and production. All the design drawings and so on are completely in accordance with the design of upstream manufacturers to carry out the manufacturing process, the straightforward saying is the foundry. At present, the ma

The difference between the assembly machine and the brand machine: Here is a simple talk about the difference between the brand machine and their own assembly computer. Emphasize that, at present all brand machines are assembled machines, but the brand machine is a large volume of procurement after the test, printed o

) {MapNewHashmap(); Premiumphone.put ("Apple", "IPhone"); Premiumphone.put ("HTC", "HTC One"); Premiumphone.put ("Samsung", "S5"); Iterator Iterator=Premiumphone.keyset (). iterator (); while(Iterator.hasnext ()) {System.out.println (Premiumphone.get (Iterator.next ())); Premiumphone.put ("Sony", "Xperia Z"); } } }"Main" java.util.ConcurrentModificationException at java.util.hashmap$hashiterator.nextentry (Unknown SOURCE) at Java.util.hashmap$keyiterator.next (Unknow

between them. More threads require more memory space. Threads may bring more "bugs" to your program, so use them with care. The termination of a thread requires consideration of its impact on the program's operation. Typically, block model data is shared across multiple threads, and it is necessary to prevent thread deadlock situations from occurring. Summarize:the

There has been a period of time in which Twitter has been replaced by micro-letters, and it turns out that this is not the case, that Weibo has not been replaced, it has been listed and is now worth 4 billion or 5 billion of dollars. In fact, early in the micro-blog just out of time, some people say that micro-Bo will replace QQ, now QQ is not the same running,