Why do we store data in separate tables and not in one big table? Explain to me how we take an ERD and translate boxes and lines in the ERD into a SQL statement. What is needed in order to design an ERD? What is needed to work with multiple tables in a SQL statement?
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Zhibin Wang says
We store the data in a separate table instead of storing it in a large table because we need to process the information in a more direct way. The data table needs to be linked to another table through their relationship when we store the data through the primary key. In order to design ERD, we need to know and understand relationship about entities, entity attributes, primary keys. ERDs contain different symbols and connectors. They can visualize two kinds of information: the main entities of the system and the relationship between these entities.
Jason Poli says
Storing data in separate tables allows a database to function more efficiently, and keeps data organized based on the specifics of each table. A system may have trouble retrieving data from one big table vs separate tables, if much of the data in aggregate is inapplicable to what an end user is requesting. An entity relationship diagram (ERD) shows us the relationships between all the various tables in a single database, and an ERD provides a useful blueprint which we can reverse engineer into mySQL source code to run queries and generate tables and information useful in making business decisions. To design an ERD you need a Visual Paradigm (one is provided MySQL Workbench). This tool lets you create the tables of your database with the necessary rows and columns, to help model the relationships. To work with multiple tables you need to understand the relationship between then and create the columns of each table to share some type of attribute, like a User ID. When relations are set, one can use commands like SELECT, INSERT, UPDATE, and DELETE, to work with the data in the tables designed, and run queries for information needed to make decisions or for and application to complete specific tasks.
Lingyi Xu says
We store data in separate tables and not in one big table because it makes sense to combine all of these tables into one big table of related content. In addition, it may be more convenient to split them. If people can make good use of ERD in database engineering, people can generate high-quality database design for database creation, management, maintenance, and provide a meaningful basis for communication between people. To work with multiple tables in a SQL statement are primary key and row, foreign Key and so on,
Junjie Han says
From the perspective of IT security, data stored separately can better protect the data.When hacked, hackers cannot download all the data at once.From the IT perspective, data stored separately can be easily and better managed, and the data managed separately makes the logic language functionality of SQL more variable.The ERD provides the relationship between each table.IT technicians can use the source code of SQL to design a new logical language that can flexibly use the separated data.
Xinyi Mao says
we store data i separate tables because it looks clear and users can see the relationship between each database and to use these data more efficiently. also, if one of database loss or be modified, technicians can restore the specific database. To design an ERD you need a Visual Paradigm, and you need to set up primary key and secondary key and build relationship between these databases.
Natalie Dorely says
Why do we store data in separate tables and not in one big table? Explain to me how we take an ERD and translate boxes and lines in the ERD into a SQL statement. What is needed in order to design an ERD? What is needed to work with multiple tables in a SQL statement?
It’s important to store data into separate tables and not one big table because this would allow the flow of the systems to work more efficiently. To take an ERD and translate the boxes and lines into a SQl statement, it’s important to use the main source/entity and incorporate it into the formula of a SQL statement. In order to design an ERD you would need an entity and incorporate all of the necessary data needed to form the ERD. To work with multiple tables in a SQL statement,an understanding of relationship must be in order to pair the tables together , using functions as well.
Louis Gusbar says
Storing information in separate small tables allows us to update a piece of information once instead of many times. In this set up we update the information on one table and then each time that information is referenced in another table, the updated information appears. Instead of updating that piece of information in every spot it would appear in one big table. We can translate and ERD into SQL statements by using the ERD as a guide that dictates which tables, keys, and relationships we must consider when writing the SQL statement. The commands are the same for every SQL statement, the ERD tell us what information to fill in between those commands. To design an ERD you need a Visual Paradigm. In order to work with 2 tables you need to understand the relationships and use and SQL statement to create an outer join or union.
Peiran Liu says
Storing in separate tables makes relationship between data more understandable. By using ERD we will have a clear view on how to build the database level by level. A logical mind is required in order to design an ERD. Relationship between multiple tables is needed when working with multiple tables.