Cara menggunakan composite attribute in mysql
ERD, short form for Entity Relationship diagram is a kind of diagram for presenting the properties as well as the relationships between data or participants. Database designer uses ERD to model physical structure of a relational database, while business analyst uses ERD to model the data that is logically required or produced by processes. In this page you will learn how to draw entity, how to add column and how to create relationship between entities. Show
Creating Entity Relationship Diagram
Drawing an entityTo draw an entity, select from the diagram toolbar and then click on the diagram. An entity will be created.
Adding column into entityTo add column into entity:
Modeling MySQL 'Set type'SET columns in MySQL allows the definition of columns that can contain a given set of values. In Visual Paradigm you can model a set type with the steps below:
Specifying primary keyThere are several ways you can take to specify a column as a primary key. When inline editing, you can type + before the column name to indicate that the column is a primary key column.
Alternatively, right click on a column and select Include in Primary Key to set the column as primary key or include it as part of a composite key. Finally, you can also find and check the Include in Primary Key option in the Column Specification window. To open the window, right click on a column and select Open Specification... from the popup menu. Clustered and non-clustered primary keyThe use of clustered primary key may make the querying of data more efficient. To make a primary key of an entity a clustered/non-clustered primary key:
Hiding nullable icons in ERDIn case you want to hide the nullable icon (as represented by symbol N) in ERD, you can follow the steps below: Right click on the diagram > Presentation Options > Entity Columns Display Options> Column Constraints Presentation Option> uncheck Show Nullable. Selecting all columns in an entityTo select all columns within an entity, select any column first, and then press Ctrl-A to select the rest. Working with relationshipsCreating an entity with relationshipRelationship shows how the entities are related to each other. You can create a related entity by performing the steps below:
Connecting to existing entityTo connect to en existing entity:
Linked entity in many-to-many relationshipWhen you create a many-to-many relationship, a linked entity will be created, with two one-to-many relationships connected to it from the source entities.
Identifying and non-identifying relationshipsThere are two types of relationships - identifying and non-identifying. Identifying relationship specifies the part-of-whole relationship. It means that the child instance cannot exist without the parent instance. Once the parent instance is destroyed, the child instance becomes meaningless. Non-identifying relationship implies weak dependency relationship between parent and child entities. There are two kinds of non-identifying relationships, including optional and mandatory. The necessity of the parent entity is "exactly one" and "zero or one" in the mandatory and optional non-identifying relationship respectively. Related ResourcesThe following resources may help you to learn more about the topic discussed in this page.
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