{"id":1985,"date":"2022-07-02T21:32:50","date_gmt":"2022-07-02T16:32:50","guid":{"rendered":"https:\/\/www.edopedia.com\/blog\/?p=1985"},"modified":"2022-07-06T12:20:26","modified_gmt":"2022-07-06T07:20:26","slug":"schemats-tutorial","status":"publish","type":"post","link":"https:\/\/www.edopedia.com\/blog\/schemats-tutorial\/","title":{"rendered":"Schemats Tutorial and Ultimate Guide For Beginners"},"content":{"rendered":"\n

Introduction: What is Schemats and Why Should You Care?<\/h2>\n\n\n\n

Schemats<\/strong> is a tool that helps you automatically generate TypeScript interface definitions from SQL database schema. It completely supports popular relational database management systems (RDBMS) like MySQL and PostgreSQL.<\/p>\n\n\n\n

This Schemats Tutorial<\/strong> will help you get started and understand the basics of this amazing tool in no time.<\/p>\n\n\n\n

Let’s say you have a database schema of the “Users”<\/strong> table something like this:<\/p>\n\n\n\n

Name<\/th>Type<\/th><\/tr><\/thead>
id<\/td>SERIAL<\/td><\/tr>
email<\/td>VARCHAR<\/td><\/tr>
password<\/td>VARCHAR<\/td><\/tr>
last_seen<\/td>TIMESTAMP<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

<\/p>\n\n\n\n

Now, Schemats can automatically generate the following TypesScript Interface for you.<\/p>\n\n\n\n

interface Users {\n    id: number;\n    email: string;\n    password: string;\n    last_seen: Date;\n}<\/pre>\n\n\n\n
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How to Install Schemats?<\/h2>\n\n\n\n
The Schemats library is available on npm (Node Package Manager). So, you can easily install it by executing the below-mentioned command in your terminal.<\/p>\n\n\n\n
npm install -g schemats<\/pre>\n\n\n\n
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Generate TS Interface Definition from Schema<\/h2>\n\n\n\n
Let’s say you have a database named “company” with a table “users”. Now, to generate a TypeScript interface definition from your schema, simply run the below command.<\/p>\n\n\n\n
For PostgreSQL, use this command:<\/strong><\/p>\n\n\n\n
schemats generate -c postgres:\/\/postgres@localhost\/company -t users -o company.ts<\/pre>\n\n\n\n
For MySQL, use this command:<\/strong><\/p>\n\n\n\n
schemats generate -c mysql:\/\/mysql@localhost\/company -t users -o company.ts<\/pre>\n\n\n\n
These commands will generate the typescript interfaces for the “company”<\/strong> database with table “users”<\/strong> inside a new file called “company.ts”<\/strong>.<\/p>\n\n\n\n
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Using schemats.json config file<\/h2>\n\n\n\n
Schemats is well equipped to read configuration options from a JSON config file. By default, this config file is known as “schemats.json”<\/strong>. So, if you don’t want to provide the command-line parameters as we did in our previous example, you can instead define the configurations inside the config file.<\/p>\n\n\n\n
For example, add the following configuration options inside schemats.json. Note:- Don’t forget to place the schemats.json file in the current working directory.<\/em><\/p>\n\n\n\n
{\n    \"conn\": \"postgres:\/\/postgres@localhost\/company\",\n    \"table\": [\"users\"],\n    \"output\": \"company.ts\"\n}<\/pre>\n\n\n\n
Now, executing schemats generate<\/code> here is the same as executing schemats generate -c postgres:\/\/postgres@localhost\/company -t users -o company.ts<\/code><\/p>\n\n\n\n
Here I’m listing all the available configuration options you could use inside the config file.<\/p>\n\n\n\n
Option Name<\/th>Type<\/th><\/tr><\/thead>
conn<\/td>string<\/td><\/tr>
table<\/td>string[] or string<\/td><\/tr>
schema<\/td>string<\/td><\/tr>
output<\/td>string<\/td><\/tr>
camelCase<\/td>boolean<\/td><\/tr>
noHeader<\/td>boolean<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
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Write Code with Typed Schema<\/h2>\n\n\n\n
By the way, we can also import our output file (such as “company.ts<\/strong>“) directly inside the code. It allows us to write code with autocompletion<\/strong> and static type checks<\/strong> because the type definition for our database schema was already generated.<\/p>\n\n\n\n
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Real-world Usecase of Schemats<\/h2>\n\n\n\n
The below flow\/chain is unavoidable if the UI needs to show information that the database schema currently doesn’t have.<\/p>\n\n\n\n