正文

good practice

(2014-07-28 17:05:11) 下一個
don't use * in the query ( * is anti-pattern in query, which will create much work for the server )
don't omit column list in insertion (think what if a new column will be added later)
...


Ad hoc is a Latin phrase meaning "for this". It generally signifies a solution designed for a specific problem or task, non-generalizable, and not intended to be able to be adapted to other purposes. Common examples are organizations, committees, and commissions created at the national or international level for a specific task.


Ad hoc query    relatively small, random, dynamic, fast

"Ad hoc is latin for "for this purpose". You might call it an "on the fly" query, or a "just so" query. It's the kind of SQL query you just loosely type out where you need it

var newSqlQuery = "SELECT * FROM table WHERE id = " + myId;

...which is an entirely different query each time that line of code is executed, depending on the value of myId. The opposite of an ad hoc query is a predefined query such as a Stored Procedure, where you have created a single query for the entire generalized purpose of selecting from that table (say), and pass the ID as a variable."

batch processing    relatively large, predefined, takes longer time





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