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Correct way to quit a Qt program?

...ose your application from main() you can use this code int main(int argc, char *argv[]){ QApplication app(argc, argv); ... if(!QSslSocket::supportsSsl()) return app.exit(0); ... return app.exec(); } The program will terminated if OpenSSL is not installed ...
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How do you find the disk size of a Postgres / PostgreSQL table and its indexes

... Try the Database Object Size Functions. An example: SELECT pg_size_pretty(pg_total_relation_size('"<schema>"."<table>"')); For all tables, something along the lines of: SELECT table_schema || '.' || table_name AS table_full_name, pg_size_pretty(pg_total_...
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Execute stored procedure with an Output parameter?

...s to right-click on the procedure in Sql Server Management Studio(SSMS), select execute stored procedure... and add values for the input parameters as prompted. SSMS will then generate the code to run the proc in a new query window, and execute it for you. You can study the generated code to se...
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How Do I Choose Between a Hash Table and a Trie (Prefix Tree)?

...(1) (in relation to the upper bound). Maybe the longest english word is 50 characters? 8 Answers ...
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How to insert text into the textarea at the current cursor position?

...ction insertAtCursor(myField, myValue) { //IE support if (document.selection) { myField.focus(); sel = document.selection.createRange(); sel.text = myValue; } //MOZILLA and others else if (myField.selectionStart || myField.selectionStart == '0') { ...
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How do I put an 'if clause' in an SQL string?

... WHERE purchaseOrder_ID = '@purchaseOrder_ID' and not exists (SELECT * FROM itemsOrdered WHERE purchaseOrder_ID = '@purchaseOrdered_ID' AND status = 'PENDING' ) However, I might guess that you are looping at a higher level. To set all such v...
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select、poll、epoll之间的区别总结[整理] - C/C++ - 清泛网 - 专注C/C++及内核技术

select、poll、epoll之间的区别总结[整理]select,poll,epoll都是IO多路复用的机制。I O多路复用就通过一种机制,可以监视多个描述符,一旦某个描述符就绪(一般是读就绪或者写就绪...select,poll,epoll都是IO多路复用的机制。I/O多路...
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How to get number of rows using SqlDataReader in C#

...reading all rows (and then you might as well store them) run a specialized SELECT COUNT(*) query beforehand. Going twice through the DataReader loop is really expensive, you would have to re-execute the query. And (thanks to Pete OHanlon) the second option is only concurrency-safe when you use a ...
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Fastest way(s) to move the cursor on a terminal command line?

...the previous line, you can use quick substitution: ^--option25^--newoption Character search. This was mentioned by Pax, and can be done in regular emacs-mode with Ctrl+] for forward search, and Ctrl+Alt+] for backward search. I recommend the second option. Ctrl+r is really handy and fast, no mucki...
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Using IQueryable with Linq

...ram. Your program then filters the data. In essence, the database does a SELECT * FROM Products, and returns EVERY product to you. With the right IQueryable<T> provider, on the other hand, you can do: IQueryable<Product> products = myORM.GetQueryableProducts(); var productsOver25 =...