Column-Level Security with Views Perhaps using views is the best option when it comes to restricting access to a certain column or columns within a table. First, you create a view that selects all the columns from the underlying table except those ones you want to make inaccessible. Then, you grant the SELECT privilege on that view to your users,...
Oracle
Column-Level Security with DECODE
Column-Level Security with DECODE To restrict access to a certain column or columns within a table, you might create a view upon that table hiding unnecessary columns as needed. Sometimes, however, making a certain column completely inaccessible is not exactly what you’d like to get. Instead, you might mask the column values so that the user can access only those...
Joining Relational Data and XML Data In a SQL Query
Joining Relational Data and XML Data In a SQL Query In this article, you’ll look at how you might merge external XML data into an Oracle database and then join that XML data with relational data stored inside the database within a single SQL query. To follow the article sample, you’ll first need to create an XML document to be...
Combining Multiple Queries In a Single One
Combining Multiple Queries In a Single One This is often the case when you need to query more than one table in a single query, or even issue more than one subquery to a single table, combining those subqueries in a single query. There are several types of queries that come within the above description, including joins, hierarchical queries, and...
Getting Started With Hierarchical Queries
Getting Started With Hierarchical Queries Hierarchical queries return rows in the order that forms a hierarchical tree where each row is located at a certain level in a hierarchy, having a parent, children, or both. The best way to understand this concept is to build some hierarchical queries against database objects that permit it. For example, you might issue such...
Dealing With Sparse Date Data
Dealing With Sparse Date Data Generating a row per day within a specified date range is often necessary when you need to create a report showing daily results for each day in the range, regardless of whether there was an activity on a particular day or not. Suppose you need to generate a row for each day within the following...