datatypes

Oracle 11G Total Recall

Oracle Total Recall for Tracking History

Oracle 11g Flashback Data Archive (Oracle Total Recall), essentially meant as a DBA tool to recover from logical corruptions and human errors, can be put to good use for another standard requirement in applications. Most applications need an audit trail or history of changes for important entities – say, the trail of changes to customer’s […]

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How to Perform MULTISET Operations on Nested Table of Objects

We’ve seen the easy working of MULTISET operations on nested tables of simple types (i.e. collections of text, numbers). And we’ve seen the problem with extending MULTISET operations to nested tables of complex types (i.e. those based on OBJECTs with multiple attributes). PL/SQL code when run with MULTISET operations on complex collections throws up the […]

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10 Important Lessons in Data Modeling

Are you building the database for a custom OLTP application starting from scratch, with the business requirements as only initial input? No matter what the size, domain or location of your project, the following lessons will help to ensure that your physical data modeling process is smooth and that you end up with a database […]

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An Easy Guide to PL/SQL Collections

  A collection is a list of elements of the same type. Each element in the list has a unique position number or label, called the "subscript". To give a logical analogy, consider a list of colors = {red, blue, green, yellow}. This list has four elements, all names of colors. There is a unique […]

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The BOOLEAN Datatype

The Oracle database does not have the BOOLEAN datatype. No direct way to represent that a column like IS_ACTIVE on table ITEMS is TRUE or FALSE. The good news is that there are simple workarounds to the situation.

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The Difference between CHAR, VARCHAR and VARCHAR2

Oracle has three datatypes to store strings. – CHAR, VARCHAR and VARCHAR2. How do they differ from each other? When should you use which? Let’s find out the answers in this article.

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