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Database Terminology Transcription

Welcome to our Database Design Terminology Module. A table is a set of rows and columns that contains related information in a database. And it look like a spreadsheet. A tuple is a row or a record in the database. And you should remember that for the CISSB examination.

Cardinality is equal to the number of rows in the table. And the table's degree is the number of columns in a table. An attribute is another name for the column or field in a database. And you should remember attribute for the CSSP examination as well. An index is used to find records within a table more quickly.

And a cell in the table or database is the intersection or value located at the intersection of a row And column in the database. A single record is held in the cell. Here we can see an example of a sample database. You can see that the attribute column is the color so those are attributes and one example of a row or tuple is the product with G 978.

So this product G 978 is available in medium green, with a Western design. The unique primary key, G978, is a unique identifier for a specific record in the database. No two items can have the same primary key. It must be unique. Data normalization is the process of eliminating duplicates and ensuring that all attributes in a table depend only on one unique primary key.

Database denormalization involves adding extra information to the tables in order to increase performance or security. You can put in redundant information to enhance performance. And you can add false information to the tables as a security measure to avoid people from inferring data in the database. Polyunstantiation is a false data inserted in to the data base and shown to users who do not have a need to know who attempts to access records that they should not be accessing.

Rather than telling the user that they do not have a need to know and that they cannot view the record, the database simply provides them with false information in order to trick them into thinking they got the correct information. For the CISSP examination, you should know the difference between data normalization and database denormalization.

And you should also remember what polyinstantiation. A key is an attribute that provides a unique value in a tuple, or a row, that uniquely identifies that row. A candidate key is an attribute that could uniquely identify a row in a table. A given table could have several candidate keys.

Each table has one primary key that is the candidate key that the database administrator selects in order to uniquely identity each row, or tubule or record in that table. A foreign key is a cell value in one table that refers to a unique key in a different table in the same database.

This linking between tables creates table relations. Here is an example of how a foreign key could be used. The table at the top lists are different products and the primary key in this particular table is the product ID. We can only have one product with each specific product ID.

So for example, P478 is a red, large item, weighs 2 pounds, and costs $1.35. And each of the products listed in that table, such as P456 and P523, are tuples, or the rows in the databases. The descriptors for these products, like color, size, and weight Those are the columns or attributes in the database.

We then at the bottom have a child table and this table allows us to reference data from the table at the top. Here you can see they're offering a product bundle, bundle B3. This bundle includes products P478 and P235. These are foreign keys because it's using that key to look up the data from another table at the top of the screen.

In order to fill the weight in the cost by combining those values from the different products included in the bundle. This allows the database administrator to only maintain the color, size, weight and cost in the table at the top. When they have the product bundle table, they do not need to maintain that data in a second location.

They can simply refer to the table at the top, and calculate the weight and cost without having to store all of the products in the secondary table. Schemos are used in SQL, and they are basically blue Which define the structure of your database. They can also contain access controls which limit how users can view the information in the database.

A data dictionary is data about your data And it is a central repository of metadata, which contains critical information about your entire database. Metadata is just a term for data, about data, or data that gives you additional information about a certain object or item. The data dictionary can contain cross references between groups of data elements and determine how they interact with each other in relationships.

It also can contain a central collection of data element definitions, schema objects, and reference keys. This makes it very easy for you to centrally manage the database, and also includes access control lists to prohibit individuals from accessing information that they should not be accessing, and to grant authorized users access to that same information.

This concludes our Database Design Terminology Module. Thank you for watching.