Complete the following discussions about Micorsoft Access: For adding to or upda
ID: 3849345 • Letter: C
Question
Complete the following discussions about Micorsoft Access:
For adding to or updating data in a table, which do you think would be the most useful—a wizard, report, query, or form? Why?
There may be more than one way to add a column to a table. Which way do you prefer? Why?
What does customizing fields and tables mean?
Why do you think it is necessary to customize fields and tables?
How often do you think you would need to customize fields and tables?
Give reasons to support your answer.
What is database normalization and why is this concept so important to consider when designing a table?
Explanation / Answer
1.
In most of the scenarios Updating the table is done by either Query or Form.
Query:
You use update queries in Access databases to add, change, or delete the information in an existing record. You can think of update queries as a powerful form of the Find and Replace dialog box. You cannot use an update query to add new records to a database, or to delete records from a database.
Form:
You use a form to update small amounts of data. In this case, "small" means any number of records that you want to update manually. Forms can provide an easier, faster, and more accurate way to edit and update small amounts data.
Wizard:
A wizard won't update the data, but it lets you define how the data is grouped and sorted, and you can use fields from more than one table or query
Report:
A report is an object in Microsoft Access that is used to display and print your data in an organized manner.
So based on the requirement we can use Query or Form
2.
Microsoft Office Access 2007 provides several ways to add or remove the columns in a datasheet. You can now use Datasheet view to add or remove columns and set the data types for those columns. You can also add fields from a task pane, or you can open the table that underlies the datasheet and add a field in Design view.
a.Add a column by Datasheet View: By default, all tables in Datasheet view now contain a blank column labeled Add New Field. To add a column, you enter data into the first blank cell beneath that column header. You can also paste one or more pieces of data into the blank column. You no longer need to use Design view to add or remove columns, although you can if you want. In addition, you no longer have to set the more common data types for the new column. By default, the fields in a database table must contain specific types of data, such as text, dates and times, numbers, and so on. Typically, you set data types when you design the tables for a database. However, Access now infers most data types when you first enter data in a new column. For example, if you enter a name in the first field in your new table, Access sets that field to the Text data type. If you paste a date, Access sets the field to the Date/Time data type, and so on. If you paste a mix of data, such as postal codes from several countries/regions, Access selects the data type that does the best job of preserving the information.
b. Add a column by Design View: Design view provides greater flexibility than Datasheet view because you can set all available data types, and you can create a lookup field, all without having to leave Design view.
Based on the requirement, if you want the data type to be set automatically you can use datasheet view. or else if you want to set the data type manually, you can use design view.
3. Customization of field or table means giving user defined attributes to the entity. For example for a column ID we can give it should not be empty, then that column is customized column and table is customized table.
4. Necessity of customizing field and tables: Almost in every DB customization is compulsary as it is user specified.
For example if Column ID is a unique attribute of the table, and if it not customized, it may contain duplicate values or null values, which results in the data loss.
So customization is must for a field as well as table.
5. Database Normalization:
Database normalization, or data normalization, is a technique to organize the contents of the tables for transactional databases and data warehouses. Normalization is part of successful database design; without normalization, database systems can be inaccurate, slow, and inefficient, and they might not produce the data you expect.
When you normalize a database, you have four goals: arranging data into logical groupings such that each group describes a small part of the whole; minimizing the amount of duplicate data stored in a database; organizing the data such that, when you modify it, you make the change in only one place; and building a database in which you can access and manipulate the data quickly and efficiently without compromising the integrity of the data in storage.
Data normalization helps you design new databases to meet these goals or to test databases to see whether they meet the goals. Sometimes database designers refer to these goals in terms such as data integrity, referential integrity, or keyed data access. Ideally, you normalize data before you create database tables. However, you can also use these techniques to test an existing database.
Data normalization is primarily important in the transactional, or online transactional processing (OLTP), database world, in which data modifications (e.g., inserts, updates, deletes) occur rapidly and randomly throughout the stored data. In contrast, a data warehouse contains a large amount of denormalized and summarized data—precalculated to avoid the performance penalty of ad hoc joins. In a data warehouse, updates happen periodically under extremely controlled circumstances. End users' updates to data in data warehouses are uncommon.