Social media surrounds us, so it’s not unusual for applications to require some kind of social media integration. The most common issigning in with Facebook, Twitter, or another service. Users expect to be able to log in with different social accounts. So, applications meet these expectations by offering external login options. Let’s take a look at this functionality and investigate how to merge users’ accounts – specifically, we’ll consider the situation when people use several methods to log in.

The most recognizable characteristic of crow’s foot notation (also known as IE notation) is that it uses graphical symbols to indicate the ‘many’ side of the relationship. The three-pronged ‘many’ symbol is also how this widely-used notation style got its name. Let’s see where crow’s foot is placed in the history of data modeling and take a look at its symbols. History: How Crow’s Foot Notation Got Started The beginning of crow’s foot notation dates back to an article by Gordon Everest (1976, Fifth Computing Conference, IEEE).

Various ERD notations follow different styles for entities, relationships, and attributes. Usually there isn’t much standardization between them, so notations bear little resemblance to each other. Among the plethora of ERD diagram notations, crow’s foot notation is definitely the most used. In this article, we’ll investigate its components within the Vertabelo database model. Before we start looking into crow’s foot notation, we must understand that there are various levels of Entity-Relationship diagrams: conceptual data model – an overview of what should be included in the general database model.

Handling user registration and authentication isn’t an easy task. Both users and developers understand this. Users have to select and remember another username and password (taking into account different password policies, of course). A developer’s responsibility is to make this process secure and to properly protect the user’s data. So it’s no surprise that logging in with one account – Facebook or Google, for example – is extremely popular.

Level: Beginner So many organizations face the common problem of storing employee schedules. No matter what institution: a company, a university or simply an individual, many entities need an application to view schedules. Therefore, I will try to come up with a database model and then, in a future article, we’ll talk about a simple application to store employees’ schedules in a database. Currently the design looks as follows:

In this article, I’ll make a comparison of two popular database modelers: Vertabelo in version 1.21.0 and Navicat Data Modeler in version 1.0.12. Features are listed in the left-hand column and each tool’s feature support is identified under the appropriate heading. Vertabelo Navicat Data Modeler Online tool works under Chrome OS independent Standalone version available for: Linux Mac OS X Windows Model structure Tables References Sequences Views Text Notes Indexes Checks Additional SQL scripts Supported database engines PostgreSQL MySQL MS SQL Server Oracle SQLite HSQLDB IBM DB2 PostgreSQL MySQL MS SQL Server (Windows and Mac OS X editions only) Oracle SQLite SQL Azure (Windows and Mac OS X editions only) Supported data types Vertabelo supports a particular database from creation.

In this article, I will compare two online database modelers: Vertabelo and Sea Quail Database Diagram Tool. Here is a matrix of each tool’s key features and functionality. Compared versions: Vertabelo 1.14.3, Sea Quail v.32. Vertabelo Sea Quail Model structure Tables References Sequences Views Text Notes Indexes Checks Additional SQL scripts Supported database engines PostgreSQL MySQL MS SQL Server Oracle SQLite HSQLDB IBM DB2 PostgreSQL MySQL MS SQL Server Supported data types Vertabelo supports particular database from the begining.

The Vertabelo journey continues … We now have almost 10,000 users and the number of Vertabelo advocates keeps growing strong. Vertabelo users come from over 100 countries and speak various languages. What unites them? The relational database. Let’s see what relational databases they use: We wanted to determine the most popular database engine among Vertabelo users based on one of three widely-used operating systems: Windows, Linux, Mac OS.

UML is popular for its notations. We all know that UML is for visualizing, specifying, and documenting the components of software and non software systems. What’s more, UML has many types of diagrams which are divided into two categories. Some types represent structural information, others general types of behaviors. Among these, there is one that is commonly used for entity relationship diagrams. In UML, an entity is represented by a rectangle:

Arrow notation has become one of the less recognized notations in entity relationships diagrams in recent years. Let’s discuss its elements. Entity and relationships As you can see below, an entity is always represented by a rectangle, which is common to most notations (there isn’t a distinction if it is dependent or independent entity). Relationships and cardinality are represented by various combinations of arrows as the diagram below presents.