字幕列表 影片播放 列印英文字幕 to complete our theoretical preparation, we will need to learn more database terminology. This is a necessary step that will help us when we start coating an SQL later. Let's go through the entire process of creating a database. Assume our database containing customer sells data has not been set up yet. Okay, So imagine you are the shop owner, and you realize you have been selling goods quite well recently and you have more than a 1,000,000 rows of data. What do you need then? A database. But you know nothing about databases. Who do you call an SQL specialist? No. You need a database designer. She will be in charge of deciding how to organize the data into tables and how to set up the relations between these tables. This step is crucial. If the database design is not perfect from the beginning, your system will be difficult to work with and wouldn't facilitate your business needs. You will have to start over again, considering the time and data and money involved in the process. You want to avoid going back to 0.0. What do database designers actually do? They plot the entire database system on a canvas using a visualization tool. There are two main ways to do that. One is drawing an entity relationship diagram an E R diagram for brief. It looks like this. And as its name suggests, the different figures represent different data entities and the specific relationships we have between entities. The connections between tables are indicated with lines. This way of representing databases is powerful and professional, but it is complicated. We will not focus in depth on E. R diagrams in this course, but you should know they exist in referred to the process of database design. Another form of representation of a database is the relational schema. This is an existing idea of how the database must be organized. It is useful when you're certain of the structure and organization of the database you would like to create. More precisely, a relational schema would look like this. It represents a table in the shape of a rectangle, the name of the tables at the top of the rectangle. The column names are listed below all relational schemers in a database form the database schema. You can also see lines indicating how tables are related in the database as you probably noticed we have some other features, but we will leave their explanation for the next lecture. Once the database design process is done, the next step would be to create the database. To this moment, it has been ideas, planning, abstract thinking and design. At this stage, it would be correct to say SQL could be used to set up the database physically, as opposed to contriving it abstractly. Then you can enjoy the advantages of data manipulation. It will allow you to use your data set to extract business insights that name to improve the performance and efficiency of the business you are working for. This process is interesting, and practically the main part of the course will be related to that. Remember, well thought out Databases that are carefully designed and created are crucial prerequisites for data manipulation. If you have done good work with these steps, we could write effective queries and navigate in a database rather quickly. You will often hear the term database management. It comprises all these steps of business undertakes to design, create and manipulate its databases successfully. Finally, database administration is the most frequently encounter job amongst all the database administrator is the person providing daily care and maintenance of a database. Her scope of responsibilities is narrower regarding the ones carried out by a database manager, but she is still indispensable for the database department of a company. This lecture allowed us to learn certain terms he will be using often when dealing with the data basis. I can't wait to get to the next video, where we will explain how meaningful our relational scheme it can be for you to understand the functioning of a certain database. See there.