Sybase

No matter which hard disk brand you have, it is simply a matter of your time before you’ll need data recuperation. Whether it is a result of mechanical failure …

There are three levels of data modeling. They are conceptual, logical, and physical. This section will explain the difference between the three, the order with …

Tables are the basic structure where data is stored in the database. Given that in most cases, there is no way for the database vendor to know ahead of time …

Views can be considered as virtual tables. Generally speaking, a table has a set of definition that sets the structure of the table, and physically stores the …

Indexes help us retrieve data from tables quicker. Let’s use an example to illustrate this point: Say we are interested in reading about how to grow peppers in …

Once a table is created in the database, there are many occasions where one may wish to change the structure of the table. Typical cases include the following: …

A primary key is used to uniquely identify each row on a table. It can either be part of the actual record itself, or it can be an artificial field (something …

A foreign key is a field (or fields) that points to the primary key of another table. The purpose of the foreign key is to ensure referential integrity of the …

Sometimes we may decide that we need to get rid of a table in the database for some reason. In fact, it would be problematic if we cannot do so because this …

Sometimes we wish to get rid of all the data in a table. One way of doing this is with DROP TABLE, which we saw in the last section. But what if we wish to …

In the previous sections, we have seen how to retrieve information from tables. But how do these rows of data get into these tables in the first place? This is …

Once we have the information in the table, we might find that there is a need to modify the data. To do so, we can use the UPDATE command. The syntax for this …