Golang Go Get Postgres Error

You are dealing with error handling in Go when working with PostgreSQL using the pq package. The code you provided demonstrates two different ways to handle and extract error information from a pq.Error type.

Let’s break down both of these code snippets:

1. Using Type Assertion:

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pqErr := err.(*pq.Error)
log.Println(pqErr.Code)

In this code, you are using a type assertion to check if the err is of type *pq.Error, and if it is, you extract the Code field from the pq.Error struct and log it. This approach assumes that err is a pq.Error type, and if it’s not, it will result in a runtime panic. So, it’s essential to be sure that err is indeed of type *pq.Error before using this approach.

2. Using Type Assertion with Ok Idiom:

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if err, ok := err.(*pq.Error); ok {
    fmt.Println(err.Code)
}

This code is similar to the first one but incorporates the “comma, ok” idiom. It first attempts to perform a type assertion to check if err is of type *pq.Error. If the assertion is successful (i.e., ok is true), it prints the Code field. This approach is safer because it doesn’t panic if the type assertion fails.

In both cases, err.Code is used to access the error code associated with the pq.Error instance. PostgreSQL error codes provide specific information about the error that occurred during a database operation. You can use these error codes to handle different types of errors gracefully in your Go application.

Make sure to import the pq package at the beginning of your Go file like this:

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import (
    "database/sql"
    "github.com/lib/pq"
    // other imports
)

Additionally, ensure that you have imported the required packages and have properly set up your PostgreSQL database connection before using these error-handling methods.