dk

README

README

Database Kit in golang.

This package contains following sub packages:

• cue ... query builder
• ef ... execution facade
• dialect ... DBMS dialects

How to use?

go get

go get bitbucket.org/shu/dk

cue -- query builder

import "bitbucket.org/shu/dk/cue"
sel := cue.Select().From("users").Where(cue.Eq("id", 100))
query, args := sel.BuildSQL()
// db.QueryRow(query, args...).Scan(...)

ef -- execution facade

import "bitbucket.org/shu/dk/ef"
import "bitbucket.org/shu/dk/dialect"
type User struct {
    ID       int
    UserName string `db:"name"`
    Age      int    `db:"-"`
}
var u User
// query, args := cue.Select().From("users").Where(cue.Eq("id", 100)).Dialect(dialect.MySQL{}).BuildSQL()
query, args := "SELECT * FROM users WHERE id = ?", []interface{}[100]
if err := ef.FetchOne(db, &u, query, args...); err == nil {
    // u.ID == 100, u.UserName == "name100", u.Age == 0
}

Fetch family:

• ef.FetchOne
  • fetchies into struct, map[string]interface{}, interface{} (for unknown type value) and fetchable type.
• ef.FetchAll
  • at once, fetchies into []struct, []map[string]interface{}.
• ef.FetchEach
  • rows.Next, rows.Scan loop method.
  • Struct, map[string]interface{}, interface{} (for unknown type value) and fetchable types are supported.

Exec family:

• ef.Exec
• ef.Insert
• ef.Update
  • needs struct that has db-tagged fields (pk).
• ef.Create
  • needs struct that has db-tagged fields.

`db` tag

You can specify columns related to fields in db tag.

Outlook:

type Table1 struct {
    ID   int    `db:"id; type=serial; pk"`
    Name string `db:"name; type=varchar; size=10; default='nanashi'"`
    Age  int    `db:"age; type=integer; null"`
    Hoge int    `db:"-"`
}

In `db` tag, each element is separated by ; (semicolon).

First element is the column name. If this is - (hyphen), this field has no relationship to any columns.

The latter elements are:

• **type = **VALUE
  • type name
• **size = **VALUE
  • length, precision and scale expression in each DBMS notation
• **default = **VALUE
  • default value in raw expression ('aaa' for character type, 10 for integer type)
• pk or primarykey
  • if it is one of primary keys
• null
  • NULL-able, otherwise, NOT NULL is applied
• serial or auto_increment
  • (or type:serial-family)
  • excluded from ef.Insert

What is this repository for?

• Simple
• Easy to use
• Speedy