You’ll hear it from many people, the biggest problem in many applications is the non-use of bind variables. Oracle bind variables are a super important way to make Oracle SQL reentrant.
Bind variables does well on most of the cases, but there are some rare cases that can reduce performance. Remember, the main idea on bind variables is to preserve the sql text, so, get the same hash value, so, skip parsing, so, use the same execution plan for the *same* (or it's better to say "similar", but neither the same, nor similar, let's invent a new word: "sameilar" :) ) queries. But there are some cases, especially for tables that has large clustering factor, or the data is not homogenous, or for partitioned tables, the optimizer will generate different execution plans for that "sameilar" queries. So with using bind variables, we force the optimizer to use the same execution plan, usually.
Q: Under what conditions, autotrace & explain plan can not give the correct execution plan of a sql?
A: To start with the answer to this - we need to understand that autotrace is just a feature of SQL Plus that automates an explain plan for us - so, autotrace and explain plan are sort of synonymous in this regard. I'll be using Oracle 10g Release 2 in these examples and will be using autotrace or sql_trace=true and TKPROF - you can get the same results in 9i and later using EXPLAIN PLAN and DBMS_XPLAN.DISPLAY to see the results. ..
Merhaba, uzun bir aradan sonra yazı dizisine devam ediyorum :) Turkcell'de işler yoğunlaştı,stajyer hiç stajyer gibi olmadığı için, hepimiz gerçek projelerde çalışmaya devam ediyoruz, bu aralar da benim üzerinde çalıştığım proje için yoğundu o yüzden fazla birşey yazamadım. Ama haftasonunu kendime ayırıp 5-6 giriş yazmayı düşünüyorum, ha bu durumda kend
me mi bilgisayarıma mı ayırmış olacağım haftasonunu o tartışılır ama zaten bilgisayarlarla bütünleştiğim için çok birşey değişmeyecektir :)
Bu makalede, 23.07.2007 ve 24.07.2007'de 2 ayrı sunum yapmış olan
Hakkı Oktay'ın ilk sunumu üzerinden geçeceğiz. İlk konumuz Export, Import ve SQL Loader.
Merhaba, bu makalede 24.07.2007'de Hakkı Oktay'ın yaptığı Autonomous Transactions
ve Dynamic SQL sunuma göz atacağız. Hakkı abinin sunumu gerçekten güzeldi, her developer'ın bilmesi gereken bir konu Dynamic SQL. Autonomous Transaction konsepti de önemli.
This was actually my presentation on Aug 6, 2007 in Turkcell, about "Object Datatypes and Object Views" but I will write more on this article. This article consists of three parts.
Oracle is a relational database, but it has a great feature of object-oriented abstraction. Hence, you can use Oracle as a fully object-oriented database and develop your applications on this was. Also, you can use this object-oriented features on your relational schema, without modifying the relational data, just using object views.
Part-1 contains detailed overview of native datatypes and introduction to object datatypes.
This was actually my presentation on Aug 6, 2007 in Turkcell, about "Object Datatypes and Object Views" but I will write more on this article. This article consists of three parts.
Part-2 contains an article about object types and collection types.
This was actually my presentation on Aug 6, 2007 in Turkcell, about "Object Datatypes and Object Views" but I will write more on this article. This article consists of three parts.
Part-3 contains an article about object tables, object views and REFs.
Many people knows the show_space procedure of Tom KYTE. The procedure shows the space issues for an object, given in parameters. Execution of procedure is simple, and statistics are good. But, in AskTom, the show_space procedure has many versions :) and it's hard to know which is the last version. Also, the procedures can thow some errors in some cases and it is sometimes hard to clarify the error. In this topic, I will deal with them and give the code of last-version, running show_space code :)
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