cdr traps

Trigger creation traps The creation of Oracle triggers differs from the creation of stored procedures, functions, and packages. Trap 1: The current schema is inconsistent with the trigger owner. For example: The current login schema is R5_T150, and then execute the following create trigger: create or replace trigger "R5_T135".TRI_forbidden_01 before update or delete of GOODSCODE on t_goodsbegin RAISE_APPLICATION_ERROR(-20002, 'forbidden opera

I2C bus learning-check for missing traps-S3C2440 I2C Controller After learning the theoretical part of the IIC bus protocol, I think we should learn how to operate the 2440 IIC controller. After all, it is all about learning the S3C2440, so I will add this part. The I2C interface of S3C2440 can work in four modes: Host transmitter, host receiver, slave transmitter, and slave receiver. Shows its internal structure. We can see that the S3C2440 provid

types and value types frequently to avoid falling into the performance trap. 3. Use of null merge operators. The null merge operator is introduced in C #2.0. First ?? Second: (1) Evaluate first. (2) If first is not null, the value of the entire expression is the value of first. (3) Otherwise, calculate the value of second as the value of the entire expression. Sample Code 1: when the first parameter is not null, the value of the entire expression is the first parameter no matter whether the sec

20140508 1. SQL statement, splicing query, adding single quotation marks for the string type, using =, and directly assigning values for the integer type // Method 1 String SQL = "select ID, name from table_temp where name = 'host' Limit 30 offset 20 "; DB. rawquery (SQL, null ); // Method 2 can I say it is not verified? String SQL = "select ID, name from table_temp where name =? Limit? Offset? " DB. rawquery (SQL, new string [] {name_value, limit_value, offset_value }); 2. fuzzy query, using

Question: Click to open the link Find the duplicate number. The first reaction is map (which they use for hash), which is easy to write (I am a pointer to the weak slag). However, some traps have been found during actual application, leading to several wa. The principle is very simple: Create a table, convert it to a number, ignore the horizontal bar, add it to the map, and automatically open the memory ++ according to the features automatically manag

First of all, it should be noted that I am not a theoretical school and seldom try to read out-of-class books. I just need to find them when I use them. Therefore, there are deficiencies in theory, leading to insufficient understanding of the "traps" in this article. Of course, for some friends with strong professional knowledge, this is not a "trap", but for my current knowledge level. Let's give an example to better illustrate the situation. Assume

traditional industry in the accumulation of original capital has been preliminarily completed, the Internet circle, The big one in addition to Alibaba is mostly relying on entertainment, of course, Google and Baidu can be counted as a link in the SMB market, and nothing more. Entrepreneurial class is basically barefoot, like me just looking around for shoes, I am afraid of the opportunity and the Bille of the trap is the latter account for the bulk. Asymmetric information, is an opportunity, bu

in a sequential container will invalidate the iterator pointing to this element and subsequent elements.I summarized it and thought back to the code I modified at the time, so the correct method should be as follows:1. For node-type containersSTD: List ...STD: List For (; iter! = MList. End ();){If (...){// Because the node type will only cause the current node iterator to become invalid, the iterator will be moved back when the node is deleted, because other elements will not become invalid.ML

:0.000009, percent:0.45N=18, fib:0.000004, fibi:0.000009, percent:0.45N=19, fib:0.000004, fibi:0.000009, percent:0.45N=20, fib:0.000003, fibi:0.000010, percent:0.29N=21, fib:0.000004, fibi:0.000009, percent:0.45N=22, fib:0.000004, fibi:0.000010, percent:0.40N=23, fib:0.000004, fibi:0.000010, percent:0.40N=24, fib:0.000004, fibi:0.000011, percent:0.35N=25, fib:0.000004, fibi:0.000012, percent:0.33N=26, fib:0.000004, fibi:0.000011, percent:0.34N=27, fib:0.000004, fibi:0.000011, percent:0.35N=28, f

ConceptStatic Collider: objects are checked for static statics, with Collider components and no rigidbody components.The trap of the static collision bodyWhen the game is initialized, unity merges all the static collisions into a large collider,unity that the objects cannot be moved in the game. But if you accidentally move the positions of these static collisions (which can be moved) in the game, it can cause a serious performance problem, and all the other static collisions that merge with the

DWORD ptr [ebp-104h],ecx 0008506E mov edx,dword ptr [ebp-104h]00085074mov DWORD ptr [Result],edxAvoid compiler generation of type conversions other than expected by explicitly calling ' Test.m_value (). C_STR () '.But remember what I said at the beginning of this article, this problem can be avoided by very good code specification, the method we need to use here is ' explicit '. By defining the constructor with one parameter as ' explicit ', we can avoid the compiler's implicit invocation of th

each function has its own num copy, and if you want to modify NUM, you must declare it with the global keyword. Like the following.6: How do I exchange two variable values using one line of code?For:Question 7: How do I add code so that no defined method calls the Mydefault method?For:The test of this question is the default method of Python, which calls method __getattr__ only if there are no method calls defined. When the Fn1 method passes in the parameter, we can add a *args indeterminate pa

() func() int { sum:=0 return func() int { fmt.Println(sum1) sum += 1 return sum } } nextNumber := getSequence() fmt.Println(nextNumber()) fmt.Println(nextNumber()) fmt.Println(nextNumber()) nextNumber1 := getSequence() fmt.Println(nextNumber1()) fmt.Println(nextNumber1()) fmt.Printl

The difference of map::erase function in different versions of STL 1. c++98 and C++11 standardshttp://www.cplusplus.com/reference/map/map/erase/ 2.PJ STL (Windows) map::erase function (C++11 standard) returns a map::iterator: iterator Map::erase(const_iterator _where); iterator Map::erase(const_iteratorconst_iterator _last); size_type Map::erase(constkey_type _keyval);3. SGI STL (Linux) The Linux implementation version of the Map::erase function (c++98 standard) returns a void:v

Bindings Events are a very complex topic in JavaScript. The times when we used inline Oncick events have passed. We should use event bubbling or delegation. For example, if we need to show a group of pictures to Lightbox window. So the following code you should never use. Here we use jquery as an example. Html: ....... Javascript (not recommended): $ (' a '). On (' click ', function () { Calllightbox (this); }）; Writing this way causes bind

Interview Trap questions: int i=0=i++; At this point I value: I end up being 0; When executing i=i++, the assignment symbol has the lowest priority and executes the i++ first; Execute i++, the program first put I value 0 into the stack, and then the I to operate + +; After i++ i is 1; Finally, the assignment is performed, the data in the stack is 0 popped, assigned to I, again i is 0; Therefore, best practice one: Do not assign values of the same variable more than once

statement, return the value saved in the local variable table Note: If you also use a return statement in Finally, such as return ++x. Then Y will be 3. Because the specification specifies that when both try and finally have a return, the return of the try is ignored and the return of finally is used.Code Listing 3: Public Static intTest () {intCount = 5; Try { Throw NewNullPointerException ("Exception error"); } finally{System.out.println ("Finally"); returncount; } } P

(a >= 2 (b = 3) >= 3) { System.out.println (" condition 3"); } System.out.println (b); System.out.println (c); }Look at the output: Conditions 1230This symbol does not produce a short-circuit function and will be judged below.Polymorphic This is very familiar to programmers, familiar with me or to say that the internet is much better, first polymorphic should be a run-time behavior, this is particularly important! Many places on the web say that rewr

There are now two tables, table1 and Table2,table1 have 10 million data (ID primary key index), Table2 has three data (UID field 3,5,7);Select * from where inch Select from table2);A blink of an eye feels that the sentence should be quick; you might be wishful thinking that you execute the statement inside the parentheses and then execute the outer Select, and the outer select uses the ID primary key speed to fly.Actually this statement executes very slowly, I test 20s here;Through explain ana

the engine I choose is MyISAM or InnoDB? Or, do I decide that the output data is in CSV format?Motive for profitAlthough MySQL is a successful open-source product, it is still a business, full of professional developers who get paid by it. While most users continue to enjoy the best possible experience from an open source license, the company is no doubt struggling to earn enough money to keep it running. This leads to a strange divergence between the "Community Edition" and the complete produc