How to Define Sequence for your ID Generator in ERD

coverIn relational database, records are identified by a unique value. We call this value the primary key. Some databases allow to control how this unique value is being generated by defining the sequence. In this article, we will show you how to model the sequence with Visual Paradigm and use as the ID Generator for your database tables.


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How to Group Entities in ERD Database Designer?

deletet-keyLast week, we showed you how to assign entities in an ERD to a schema. One of our users ask if there is any way to group entities in a logical manner, rather than setting the schema property reserved for physical database.

The answer is yes. You can make use of model or UML package to store and categories the entities in logical groups. The grouping can be seen in both the Model Structure and diagram. In this article, we will show you how to group entities in ERD database designer. In order to perform the steps described in this article, make sure you have Visual Paradigm installed.

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How to Assign Entities in ERD Database Designer to a Schema?

00-erd-schema-thumbVisual Paradigm for UML (VP-UML) comes with an ERD database designer where database developers can model physical database with Entity Relationship Diagram. The database designer supports popular database constructs like database table (called Entity in VP-UML), View, Sequence, Stored Procedure, Trigger, etc, supporting the need of database modeling for any kind of database management systems.

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How-to and Why Control the Visibility of Connectors in ERD when Reverse Database

00-erd-conn-thumbThe reverse database tool of VP-UML provides a handy approach to instantly convert a relational database into an ERD, to aid in the studying of database structure, entities properties and their inter-relationships.

Being able to study a database with an ERD is great because ERD is so easy to read and understand. However, the relationships among entities may increase the complexity of diagram when there are many entities and are highly coupled. If you just want to focus on seeing the database tables and their columns, but not pretty much interested in their inter-relationship, you can optionally form an ERD database diagram with solely entities, without including their relationships. In this article, you will see how to form an ERD from a MS SQL database, with just entities showing in the diagram. You will also learn how to optionally show the relationships.

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Personalize Database Connection Settings to Aid in Team Development

When a development team is developing a system that requires accessing a database, it is a common practice to setup local databases on each of the development environment and populate them with all the required schema of the system so that developers can develop and test the function they implement with test data in their own database, rather than working with actual data with production database.

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How to Find Out the Version of MySQL I am Using

Visual Paradigm supports data modeling with ERD and a set of engineering features like the reverse engineering and generation of database. The features are related with each other. For example, you may generate a database from physical ERD. In order to construct a data model that helps you build a database properly, you need to name the entities and their columns properly. Besides, data types of columns should be well-considered. Just to take the type ‘char’ example, there are quite a number of similar types like varchar, varchar2, nvarchar, etc. If a wrong type is chosen for any column, you may get data corruption or result in data lost.

Visual Paradigm supports all the data types you can find in any supported database management system (DBMS). You can select any data type you want for columns when drawing ERD. As the supported data types vary depending on the target version of DBMS, you need to set in the database configuration page the version of DBMS you use. With this, Visual Paradigm can list out those supported types, preventing you from selecting a non-supported type, which result in producing an inaccurate data model.

In this article, you will learn how to find out the version of your MySQL installation. Try to follow the steps get the information needed, and select the proper version range in the database configuration window of VP-UML. Read more

How to Use Customized Type in Object Relational Mapping

When defining class model for your persistent layer, a class is defined as part of the static data model instead of controller or user interface items. And the class is directly mapped to table(s) in your database. As the class is mapped to tables, its attributes is also mapped to columns in table. In order to make the mapping work, you have to model attributes with primitive types like integer, boolean, String, etc. You cannot model the attribute as any other types which are not compatible with database.

To overcome this, you can make use of ORM User Type to define customized datatype for attributes, and persistent its value into database. This article will teach you how to use ORM User Type. Read more