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GitHub - Masterminds/squirrel: Fluent SQL generation for golang

 4 years ago
source link: https://github.com/Masterminds/squirrel
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README.md

Squirrel - fluent SQL generator for Go

import "github.com/Masterminds/squirrel"

GoDoc Build Status

_Note: This project has moved from github.com/lann/squirrel to github.com/Masterminds/squirrel. Lann remains the architect of the project, but we're helping him curate.

Squirrel is not an ORM. For an application of Squirrel, check out structable, a table-struct mapper

Squirrel helps you build SQL queries from composable parts:

import sq "github.com/Masterminds/squirrel"

users := sq.Select("*").From("users").Join("emails USING (email_id)")

active := users.Where(sq.Eq{"deleted_at": nil})

sql, args, err := active.ToSql()

sql == "SELECT * FROM users JOIN emails USING (email_id) WHERE deleted_at IS NULL"
sql, args, err := sq.
    Insert("users").Columns("name", "age").
    Values("moe", 13).Values("larry", sq.Expr("? + 5", 12)).
    ToSql()

sql == "INSERT INTO users (name,age) VALUES (?,?),(?,? + 5)"

Squirrel can also execute queries directly:

stooges := users.Where(sq.Eq{"username": []string{"moe", "larry", "curly", "shemp"}})
three_stooges := stooges.Limit(3)
rows, err := three_stooges.RunWith(db).Query()

// Behaves like:
rows, err := db.Query("SELECT * FROM users WHERE username IN (?,?,?,?) LIMIT 3",
                      "moe", "larry", "curly", "shemp")

Squirrel makes conditional query building a breeze:

if len(q) > 0 {
    users = users.Where("name LIKE ?", fmt.Sprint("%", q, "%"))
}

Squirrel wants to make your life easier:

// StmtCache caches Prepared Stmts for you
dbCache := sq.NewStmtCacher(db)

// StatementBuilder keeps your syntax neat
mydb := sq.StatementBuilder.RunWith(dbCache)
select_users := mydb.Select("*").From("users")

Squirrel loves PostgreSQL:

psql := sq.StatementBuilder.PlaceholderFormat(sq.Dollar)

// You use question marks for placeholders...
sql, _, _ := psql.Select("*").From("elephants").Where("name IN (?,?)", "Dumbo", "Verna").ToSql()

/// ...squirrel replaces them using PlaceholderFormat.
sql == "SELECT * FROM elephants WHERE name IN ($1,$2)"


/// You can retrieve id ...
query := sq.Insert("nodes").
    Columns("uuid", "type", "data").
    Values(node.Uuid, node.Type, node.Data).
    Suffix("RETURNING \"id\"").
    RunWith(m.db).
    PlaceholderFormat(sq.Dollar)

query.QueryRow().Scan(&node.id)

You can escape question mask by inserting two question marks:

SELECT * FROM nodes WHERE meta->'format' ??| array[?,?]

will generate with the Dollar Placeholder:

SELECT * FROM nodes WHERE meta->'format' ?| array[$1,$2]

FAQ

  • How can I build an IN query on composite keys / tuples, e.g. WHERE (col1, col2) IN ((1,2),(3,4))? (#104)

    Squirrel does not explicitly support tuples, but you can get the same effect with e.g.:

    sq.Or{
  sq.Eq{"col1": 1, "col2": 2},
  sq.Eq{"col1": 3, "col2": 4}}
    WHERE (col1 = 1 AND col2 = 2) OR (col1 = 3 AND col2 = 4)

    (which should produce the same query plan as the tuple version)

  • Why doesn't Eq{"mynumber": []uint8{1,2,3}} turn into an IN query? (#114)

    Values of type []byte are handled specially by database/sql. In Go, byte is just an alias of uint8, so there is no way to distinguish []uint8 from []byte.

  • Some features are poorly documented!

    This isn't a frequent complaints section!

  • Some features are poorly documented?

    Yes. The tests should be considered a part of the documentation; take a look at those for ideas on how to express more complex queries.

License

Squirrel is released under the MIT License.


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