Tables are the basis in which all forms of data are saved in databases and tables themselves consist of a number of rows and columns, where each table consists of more than one column, and each column contains a specific data type. When working with SQL (Structured Query Language), whenever you create or alter a table, one of the columns that you include must include the data type. It is a requirement of the database management system to specify the data type of the column, helping to ensure that what is saved is in the correct form, which will help in avoiding errors.

Data types as a term must be understood because it is these data types which determine accurately the type of data that a column can and is able to hold. In SQL, the data types used are numerous, with the major ones including: Character types, Numeric types, Date and time types among others. It’s important to use the correct category because they all have their positive aspects and can be used for specific data. This article will focus on the use and variation of the most common SQL data types such as:

Numeric Data Types

Numbers are saved using the numeric types which to a greater extent include age, salary and price. In SQL numeric data types consist of two major forms, which include, integer and all the real numbers (floating points).

1. Integer Types:

These are for whole numbers. A column of an integer type is devoid of a decimal point; they are ideal for counting such as the number of items in stock or the number of users in a system. There are small integers, normal integers and big integers which are some of the integer types with different ranges of their storage areas.

2. Floating-point Types:

These numbers are used to store other numbers that have some precision beyond the decimal point. Floating-point numbers are best suited for storing items such as measurements, percentage or a monetary value. Because of their varying precision, there are different types of floating-point numbers, which are commonly called float or double.

Character Data Types

Character data types consist of text data such as names, descriptions, addresses, etc. Most of the databases are text based because that is what the users are most likely to use and access most of the time.

1. CHAR:

The CHAR type is a data type used to keep fixed-length strings. Moving to the next step, if there is a column that is defined as CHAR, there will be a time set where the required number of characters is never exceeded and if a database is entered with a lesser number of characters than what surrounded its area, then there will be spaces that will economically follow the character to the left. This is effective in columns where the strings in them are always of the same size like country codes or phone numbers.

2. VARCHAR:

The VARCHAR data type is used in keeping textual data which is of variable lengths. In contrast to CHAR, VARCHAR does not for the mean set any limit nor does it exceed any limit most especially relating to the size of data as it varies with the size of the datatype itself. This is more economical as it is used in columns that are likely to vary in size such as a person’s name or a description of a certain variable.

3. TEXT:

Most long strings of data, that is, those that are longer than the average size of a VARCHAR column are contained in the TEXT data type. Articles or comments make up good examples that would require large portions of textual data, thus, this form is perfect if the only concern is the size. However, there might be a few drawbacks to it based on the database system in use.

Date and Time Data Types

Date and time data types are utilized for the storage of date, time and timestamps within a database. With this data type, you are able to note down the times for such events as when an order was made to perhaps when a user last logged in.

1. DATE:

This is important for columns that only store the day but do not keep the time, for example, columns that store birthdays or event days. The DATE format is such that it is expressed as year, month, and day (e.g. 2024-12-07) or just the date without any relation to time.

2. TIME:

This can be used for stashing when a store opens or stashing for how long the meeting occurred. TIME is a date type which is unaware of any circulating event. It is merely the recording of the events carried out.

3. DATETIME:

Recording such events would be deemed impractical, therefore a data type that combines both is utilized. DATETIME is the most relevant data type because it contains both the date and time which enables one to be more accurate in terms of logging events.

4. TIMESTAMP:

As its name suggests, TIMESTAMP allows marking a time when a record was created or the time when the record was last modified, among other uses. It should be noted that in some of the databases, whenever a record is changed TIMESTAMP is updated automatically.

Boolean Data Type

The BOOLEAN data type is used to hold binary values, usually “one” and “zero,” in other words, “true” or “false.” Most of the time it is used to be indicators, for example if the user is active or if the particular order has been fulfilled.

Some DBMS (Database Management System) uses binary values in both cases 0 (false) and 1 (true) and others may use some words such as YES/NO, TRUE/FALSE. In logical representation of information in the context of databases, BOOLEAN takes a pivotal role.

Binary Data Types

BLOB Binary data type enables encodings in data forms that catalogues image, media files among others. This enables databases to contain and seek complex data that reside outside standard norms of text and numeric forms.

1. BLOB:

A binary large object, in computing, essentially refers to a collection of binary data stored as a single entity. Their range includes: pictures (graphics), video clips, databases of binary files, or those made up of more than one file.

2. BINARY:

The BINARY data type is used to store fixed length binary data. It comes into use when there is a need to store small binary objects, like encryptions or custom file formats.

Special Data Types

Apart from the common data types discussed above, there are some specialized data types which are supported by some databases. These types are created to cater for some specific types of data which do not fall under the generic ones.

1. ENUM:

The ENUM data type is one that enables you to specify the allowable values for a column. For example, you could use an ENUM to contain a list of countries, status codes or gender values. This data type makes certain that a column can only contain a limited number of specified values.

2. SET:

The SET data type is related to ENUM, but it permits a column to take any number from a defined list of values. For instance, a SET can be used to list tags or categories of a product where a product can have multiple categories.