pgtalk

More type safe SQL query building and execution using Go code generated (pgtalk-gen) from PostgreSQL table definitions. After code generation, you get a Go type for each table or view with functions to create a QuerySet or MutationSet value. Except for query exectution, all operations on a QuerySet or MutationSet will return a copy of that value. This package requires Go SDK version 1.18+ because it uses type parameterization.

status

This package is used in production https://ag5.com and https://go-toad.com and its programming API is stable since v1.0.0.

install

go install github.com/emicklei/pgtalk/cmd/pgtalk-gen@latest

examples

These examples are from the test package in which a few database tables files (categories,products,things) are generated.

Insert

m := products.Insert(
	products.ID.Set(10),
	products.Code.Set("testit"),
	products.CategoryID.Set(1))

it := m.Exec(aConnection)
if err := it.Err(); err != nil {
	....
}

or by example:

p := new(products.Product)
p.SetID(10).SetCode("testit").SetCategoryID(1)		
m := products.Insert(p.Setters()...)

Update

m := products.Update(
		products.Code.Set("testme"),
		products.CategoryID.Set(1)).
	Where(products.ID.Equals(10)).
	Returning(products.Code)

it := m.Exec(aConnection)	
for it.HasNext() {
	p, err := products.Next(p) // p is a *product.Product
	t.Logf("%s,%s", *p.Code)
}		

or by example

p := new(products.Product)
p.SetID(10).SetCode("testme").SetCategoryID(1)		
m := products.Update(p.Setters()...).
		Where(products.ID.Equals(p.ID)).
		Returning(products.Code)

Delete

m := products.Delete().Where(products.ID.Equals(10))

_ = m.Exec(aConnection)

Select

q := products.Select(products.Code).Where(products.Code.Equals("F42"))

products, err := q.Exec(aConnection) // products is a []*product.Product

Arbitrary SQL expressions

q := products.Select(products.ID, pgtalk. SQLAs("UPPER(p1.Code)", "upper"))

// SELECT p1.id,UPPER(p1.Code) AS upper FROM public.products p1

list, _ := q.Exec(context.Background(),aConnection)
for _, each := range list {
	upper := each.GetExpressionResult("upper").(string)
	...
}

SQL query records as maps

q := products.Select(products.ID, pgtalk. SQLAs("UPPER(p1.Code)", "upper"))

// SELECT p1.id,UPPER(p1.Code) AS upper FROM public.products p1

listOfMaps, _ := q.ExecIntoMaps(context.Background(),aConnection)
for _, each := range listOfMaps {
	id := products.ID.Get(each).(pgtype.UUID)
	upper := each["upper"].(string)
	...
}

Using Query parameter

p := NewParameter("F42")
q := products.Select(products.Code).Where(products.Code.Equals(p))

// SELECT p1.code FROM public.products p1 WHERE (p1.code = $1)
// with $1 = "F42"

Joins

Left Outer Join

q :=products.Select(products.Code).Where(products.Code.Equals("F42")).
    LeftOuterJoin(categories.Select(categories.Title)).
    On(products.ID.Equals(categories.ID))

it, _ := q.Exec(aConnection)
for it.HasNext() {
	p := new(products.Product)
	c := new(categories.Category)
	_ = it.Next(p, c)
	t.Logf("%s,%s", *p.Code, *c.Title)
}

Multi Join

q := offer.Select(offer.Columns()...).
	Where(offer.ID.In("01F674G8MDRAPBWA6SB1HWE2VC").And(offer.IsActive.Equals(true))).
	LeftOuterJoin(offer_buyer_permission_rel.Select(offer_buyer_permission_rel.BuyerPermission)).
	On(offer_buyer_permission_rel.OfferId.Equals(offer.ID)).
	LeftOuterJoin(offer_market_rel.Select(offer_market_rel.MarketId)).
	On(offer_market_rel.OfferId.Equals(offer.ID)).
	LeftOuterJoin(buyer_market_rel.Select().Where(buyer_market_rel.BuyerId.Equals("X1010_0100002"))).
	On(offer_market_rel.MarketId.Equals(offer_market_rel.MarketId))

t.Log(pgtalk.PrettySQL(q))

it, err := q.Exec(context.Background(), testConnect)
if err != nil {
	t.Fatal(err)
}
for it.HasNext() {
	offer := new(offer.Offer)
	permission := new(offer_buyer_permission_rel.OfferBuyerPermissionRel)
	market := new(offer_market_rel.OfferMarketRel)
	// The order and types of the entities must match the order of the non-empty Select functions used in the query
	err := it.Next(offer, permission, market)
	if err != nil {
		t.Fatal(err)
	}
	t.Log(offer)
	t.Log(permission)
	t.Log(market)
}

supported Column Types

• bigint
• integer
• jsonb
• json
• uuid
• point
• interval
• timestamp with time zone
• date
• text
• character varying
• numeric
• boolean
• timestamp without time zone
• daterange
• bytea
• text[]
• citext
• double precision
• decimal

Send me a PR for a missing type available from https://www.postgresql.org/docs/9.5/datatype.html by modifying mapping.go in the cmd/pgtalk-gen package.

custom datatype mappping

If your datatype can be aliased (use) to one of the supported types then you can define such mapping in a configuration file.

pgtalk-gen -mapping your-mapping.json

An example of such as mapping file your-mapping.json:

{
	"character(26)": {
		"use": "character varying"
	}
}

If your datatype cannot be aliased then you can write the missing logic for a datatype and an accessor type. See example test/types/real.go for such an implementation. The configuration for this mapping is:

{
	"real":{
		"nullableFieldType":"types.Real",
		"newAccessFuncName":"types.NewRealAccess",
		"imports": ["github.com/emicklei/pgtalk/test/types"]
	}
}

how to run the generator

The user in the connection string must have the right privileges to read schema information.

PGTALK_CONN=postgresql://usr:pwd@host:5432/database pgtalk-gen -o yourpackage
go fmt ./...

If you want to include and/or exclude table names, use additional flags such as:

pgtalk-gen -o yourpackage -include "address.*,employee.*" -exclude "org.*"

or views

pgtalk-gen -views -o yourpackage -include "skills.*"

(c) 2023, https://ernestmicklei.com. MIT License.