In this chapter, we will understand the need to create relationships between related tables. One of the goals of good database design is to remove data redundancy. To achieve that goal, you divide your data into many subject-based tables so that each fact is represented only once. To do this, all the common fields which… Read More »
In this chapter, we will understand the basics of relating data. Before talking about and creating relationships between different data, let us review why we need it. It all goes back to normalization. Normalization Database normalization, or simply normalization, is the process of organizing columns (attributes) and tables (relations) of a relational database to minimize… Read More »
Queries come in with many advantages. You can save and run the same query again and again, and a lot of times you want to add alternate criteria. You can add alternate criteria in the following two ways − You can use the OR operator to combine two sets of criteria. You can also use… Read More »
The best part about queries is that you can save and run the same query again and again, but when you run the same query again and again by only changing the criteria then you might consider the query to accept parameters. If you frequently want to run variations of a particular query, consider using… Read More »
Create an Update Query You can use an Update Query to change the data in your tables, and you can use an update query to enter criteria to specify which rows should be updated. An update query provides you an opportunity to review the updated data before you perform the update. Let us go to… Read More »
In MS Access and other DBMS systems, queries can do a lot more than just displaying data, but they can actually perform various actions on the data in your database. Action queries are queries that can add, change, or delete multiple records at one time. The added benefit is that you can preview the query… Read More »
Query criteria helps you to retrieve specific items from an Access database. If an item matches with all the criteria you enter, it appears in the query results. When you want to limit the results of a query based on the values in a field, you use query criteria. A query criterion is an expression… Read More »
A query is a request for data results, and for action on data. You can use a query to answer a simple question, to perform calculations, to combine data from different tables, or even to add, change, or delete table data. As tables grow in size they can have hundreds of thousands of records, which… Read More »
An Access database is not a file in the same sense as a Microsoft Office Word document or a Microsoft Office PowerPoint are. Instead, an Access database is a collection of objects like tables, forms, reports, queries etc. that must work together for a database to function properly. We have now created two tables with… Read More »
When you create a database, you store your data in tables. Because other database objects depend so heavily on tables, you should always start your design of a database by creating all of its tables and then creating any other object. Before you create tables, carefully consider your requirements and determine all the tables that… Read More »