Perfect - PostgreSQL Connector

This project provides a Swift wrapper around the libpq client library, enabling access to PostgreSQL servers.

This package builds with Swift Package Manager and is part of the Perfect project. It was written to be stand-alone and so does not require PerfectLib or any other components.

Ensure you have installed and activated the latest Swift 3.0 tool chain.

Issues

We are transitioning to using JIRA for all bugs and support related issues, therefore the GitHub issues has been disabled.

If you find a mistake, bug, or any other helpful suggestion you'd like to make on the docs please head over to http://jira.perfect.org:8080/servicedesk/customer/portal/1 and raise it.

A comprehensive list of open issues can be found at http://jira.perfect.org:8080/projects/ISS/issues

OS X Build Notes

This package requires the Home Brew build of PostgreSQL.

To install Home Brew:

/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

To install postgres:

brew install postgres

Linux Build Notes

Ensure that you have installed libpq-dev.

sudo apt-get install libpq-dev

Building

Add this project as a dependency in your Package.swift file.

.Package(url: "https://github.com/PerfectlySoft/Perfect-PostgreSQL.git", versions: Version(0,0,0)..<Version(10,0,0))

QuickStart

Add a file to your project, making sure that it is stored in the Sources directory of your file structure. Lets name it pg_quickstart.swift for example.

Import required libraries:

import PostgreSQL

Setup the credentials for your connection:

let postgresTestConnInfo = "host=localhost dbname=postgres"

let dataPG = PGConnection()

This function will setup and use a PGConnection

public func usePostgres() -> PGResult? {
    
    // need to make sure something is available.
    guard dataPG.connectdb(postgresTestConnInfo) == PGConnection.StatusType.ok else {
        Log.info(message: "Failure connecting to data server \(postgresTestConnInfo)")
        
        return nil
    }

    defer {
        dataPG.close()  // defer ensures we close our db connection at the end of this request
    }
    // setup basic query
    //retrieving fields with type name, oid, integer, boolean
    let queryResult:PGResult = dataPG.exec(statement: "select datname,datdba,encoding,datistemplate from pg_database")
    
    defer { queryResult.clear() }
    return queryResult
}

Use the queryResult to access the row data using PGRow Here is a function that uses several different methods to view the row contents

public func useRows(result: PGResult?) {
    //get rows
    guard result != nil else {
        return
    }
    
     for row:PGRow in result! {
        for f in row {
            //print field tuples
            //this returns a tuple (fieldName:String, fieldType:Int, fieldValue:Any?)
            print("Field: \(f)")
        }
     
     }
    
    for row:PGRow in result! {
    
        //raw description
        Log.info(message: "Row description: \(row)")
        
        //retrieve field values by name
        Log.info(message: "row( datname: \(row["datname"]), datdba: \(row["datdba"]), encoding: \(row["encoding"]), datistemplate: \(row["datistemplate"])")
        
        //retrieve field values by index
        Log.info(message: "row( datname: \(row[0]), datdba: \(row[1]), encoding: \(row[2]), datistemplate: \(row[3])")
        
        // field values are properly typed, but you have to cast to tell the compiler what we have
        let c1 = row["datname"] as? String
        let c2 = row["datdba"] as? Int
        let c3 = row["encoding"] as? Int
        let c4 = row["datistemplate"] as? Bool
        print("c1=\(c1) c2=\(c2) c3=\(c3) c4=\(c4)")
        
    }
}

Rows can also be accessed by index using subscript syntax:

 let secondRow = result[1]

Additionally, there are more complex Statement constructors, and potential object designs which can further abstract the process of interacting with your data.