135 lines
5.4 KiB
Markdown
135 lines
5.4 KiB
Markdown
---
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title: SQL Create Table
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---
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# SQL CREATE TABLE
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## Introduction
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This guide is an overview to the basics of the SQL `CREATE TABLE` functions.
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We will be using MySQL for all examples throughout these freeCodeCamp SQL guides. MySQL is a used frequently on websites for the backend database, 2) it's free, and is fun and easy to use.
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## Covered in this Guide
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* Creating a schema, the container for all our database objects.
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* Create a table so we have something to alter.
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* Creating a table by importing a CSV file and altering that table
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* Creating a table using the MySQL workbench tool
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We do most of this work with SQL statements in the MySQL workbench scripting tool. We will also see how to Create a table using the workbench interface instead of with SQL statements.
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## High level structure of a Relational Database
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1. Highest level; The Database; the database system installation. In this case, it’s MySQL. Called “Local instance MySQL Router” in the screen shots above.
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2. Next is a Schema; a container for the objects needed to managed data in a relational database system.
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3. Objects we create (tables, indexes, stored procedures, functions) to manage the system and its data
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## Creating a MySQL schema
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The schema is a container for a the objects required to manage the data for a given subject or process. We show examples as we progress in this guide.
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We’ll create the schema for our learning and testing using the SQL command;
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```
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create database fCC_alterTableGuide;
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```
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This instances schema structure prior to running this command
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This instances schema structure after running the SQL statement
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## Creating a table, add test data with "insert", rename the table (alter)
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We’ll create a Student Table.
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The steps will be:
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1. make sure we don’t have the table already
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2. create the table
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3. insert the test data.
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* Data Types: the student name is a character field limited to 90 characters
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* The student ID is a number (integer) (range of -2147483648 to 2147483647). This will be the primary key for the table and will auto increment when a record is added.
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* There will also be two "time-stamp" fields to play with as well
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Create statement and display of results from execution;
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Using a Select statement we'll see that the table is there but now records have been added.
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Now to insert some data and see what our new table looks like with records in it (and understand create and update timestamps);
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The first time stamp is the creation data and time and the 2nd is the update date and time. Changing a record should update ts2 but not ts1. Let's take a look.
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## Create a table with the MySql Workbench
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Right click on the "Tables" under the schema you want the new file placed in. Select Create Table.
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Complete the form as desired and click Apply
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## Create Table as Select (CTAS)
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A quick way to create a copy of a table, including data is to create table as select.
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CREATE TABLE my_table as (SELECT * FROM orig_tbl);
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## Create and populate a table by importing a CSV file
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Right click on the "Tables" under the schema you want the new file placed in. Select Table Data Import.
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Select the CSV file to import and click NEXT
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Usually you create a new table from the data, select the options desired and click NEXT
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Adjust the data types as needed and click NEXT
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Click NEXT (on this screen and the next one that is displayed) to import the data into the table
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You’ll see completion status, review and click FINISH
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## Other Material
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There is a lot more detail to cover on this topic so install MySQL and have fun!
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### Where to get MySQL
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Try [this download for Windows users[(https://dev.mysql.com/downloads/windows/)
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### MySQL documentation
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* <a href='https://dev.mysql.com/doc/refman/5.7/en/alter-table.html' target='_blank' rel='nofollow'>manual page</a>
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* <a href='https://dev.mysql.com/doc/refman/5.7/en/alter-table-examples.html' target='_blank' rel='nofollow'>examples from manual</a>
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### SQL Server documentation
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* <a href='https://docs.microsoft.com/en-us/sql/t-sql/statements/create-table-transact-sql' target='_blank' rel='nofollow'>Microsoft Docs</a>
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