Storage engines can surprise you. For example, take the CHAR data type. It expects an exact number of characters and by definition stores afixed amountof information. However, you don’t have to fill all the available CHAR space – a shorter value will work. This is so similar to VARCHAR that I decided to explore the differences between these two types.Before diving into the details, let’s start with some basic information. CHAR and VARCHAR are SQL data types dedicated to storing character values. They are available in almost every database engine. Due to database and encoding particulars, the storage of character values in CHAR and VARCHAR columns differs.
Beginning with SQL Server 2008, the datatypes which store date and time were greatly improved. Despite this, many legacy databases (and often newly developed ones) still useDatetimeandSmallDatetime, the original datatypes. Aside from the dwindling possibility of backwards compatibility issues, there is no advantage to using these old datatypes; as this article will show, the new implementations are superior in every way.SQL 2005 and Earlier: Datetime and SmallDatetimeDatetimeandSmallDatetimeare the original temporal SQL Server datatypes, and the only options available in SQL Server 2005 and earlier. During this time, SQL Server date support was widely criticized for its lack of options. Other database systems, such as Oracle, already featured individual datatypes for date and time, as well as specific functionality for time zones.
Sometimes you may want to use a data type that is so new that Vertabelo doesn’t recognize it. In such cases, the application displays a warning that the data type is not supported. If you find these warnings too distracting, you can turn them off. In this post, we will show you how to do it.Let’s take a look at the following example.Assume that you have a database model for MySQL 5.5. Note that one of the columns uses the JSON data type which has only been introduced in
This one is frequently asked on our support: “In the data types panel, I can’t find the data type I need. Does this mean I cannot use it in Vertabelo ?”Of course, you can. Vertabelo will never let you get stuck in a data type dead end. Even if the type you need is not listed, it doesn’t mean you cannot use it. Data types you can find under the button are just the
A common challenge for database modellers is deciding which data type is the best fit for a particular column. It is a problem which involves consideration of both the properties and the scale of the data that will be stored, and in no case is this more evident than when handling numeric values because of the large variety of alternatives that most relational databases provide for their storage.In this article we’ll explore the numeric data types available in SQL Server and analyse their advantages, disadvantages and general usage.
When designing a database, early decisions can have a huge impact on the performance and storage requirements. These decisions can be difficult to change later, as most subsequent work will depend on the physical model. This article highlights some common design decisions, flaws, and misconceptions.Creating a Primary Key: Uniqueidentifer or IntegerWhen defining a surrogate primary key for a table, two options are the most common: Integer and UniqueIdentifier (aka.Globally Unique Identifiers
Vertabelo presents part 2 of our Database Design 101 series that brings you easy-to-understand introduction to databases. This time we will focus on table columns and most commonly used data types.