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开源软件名称:go-gorp/gorp开源软件地址:https://github.com/go-gorp/gorp开源编程语言:Go 99.4%开源软件介绍:Go Relational PersistenceUpdate 2016-11-13: Future versionsAs many of the maintainers have become busy with other projects, progress toward the ever-elusive v2 has slowed to the point that we're only occasionally making progress outside of merging pull requests. In the interest of continuing to release, I'd like to lean toward a more maintainable path forward. For the moment, I am releasing a v2 tag with the current feature set from master, as some of those features have been actively used and relied on by more than one project. Our next goal is to continue cleaning up the code base with non-breaking changes as much as possible, but if/when a breaking change is needed, we'll just release new versions. This allows us to continue development at whatever pace we're capable of, without delaying the release of features or refusing PRs. IntroductionI hesitate to call gorp an ORM. Go doesn't really have objects, at least not in the classic Smalltalk/Java sense. There goes the "O". gorp doesn't know anything about the relationships between your structs (at least not yet). So the "R" is questionable too (but I use it in the name because, well, it seemed more clever). The "M" is alive and well. Given some Go structs and a database, gorp should remove a fair amount of boilerplate busy-work from your code. I hope that gorp saves you time, minimizes the drudgery of getting data in and out of your database, and helps your code focus on algorithms, not infrastructure.
InstallationUse VersioningWe use semantic version tags. Feel free to import through Development is not very active right now, but we have plans to
restructure The Check the version tags to see what's available. We'll make a good faith effort to add badges for new versions, but we make no guarantees. Supported Go versionsThis package is guaranteed to be compatible with the latest 2 major versions of Go. Any earlier versions are only supported on a best effort basis and can be dropped any time. Go has a great compatibility promise. Upgrading your program to a newer version of Go should never really be a problem. Migration guidePre-v2 to v2Automatic mapping of the version column used in optimistic locking has
been removed as it could cause problems if the type was not int. The
version column must now explicitly be set with
Help/SupportUse our Quickstartpackage main
import (
"database/sql"
"gopkg.in/gorp.v1"
_ "github.com/mattn/go-sqlite3"
"log"
"time"
)
func main() {
// initialize the DbMap
dbmap := initDb()
defer dbmap.Db.Close()
// delete any existing rows
err := dbmap.TruncateTables()
checkErr(err, "TruncateTables failed")
// create two posts
p1 := newPost("Go 1.1 released!", "Lorem ipsum lorem ipsum")
p2 := newPost("Go 1.2 released!", "Lorem ipsum lorem ipsum")
// insert rows - auto increment PKs will be set properly after the insert
err = dbmap.Insert(&p1, &p2)
checkErr(err, "Insert failed")
// use convenience SelectInt
count, err := dbmap.SelectInt("select count(*) from posts")
checkErr(err, "select count(*) failed")
log.Println("Rows after inserting:", count)
// update a row
p2.Title = "Go 1.2 is better than ever"
count, err = dbmap.Update(&p2)
checkErr(err, "Update failed")
log.Println("Rows updated:", count)
// fetch one row - note use of "post_id" instead of "Id" since column is aliased
//
// Postgres users should use $1 instead of ? placeholders
// See 'Known Issues' below
//
err = dbmap.SelectOne(&p2, "select * from posts where post_id=?", p2.Id)
checkErr(err, "SelectOne failed")
log.Println("p2 row:", p2)
// fetch all rows
var posts []Post
_, err = dbmap.Select(&posts, "select * from posts order by post_id")
checkErr(err, "Select failed")
log.Println("All rows:")
for x, p := range posts {
log.Printf(" %d: %v\n", x, p)
}
// delete row by PK
count, err = dbmap.Delete(&p1)
checkErr(err, "Delete failed")
log.Println("Rows deleted:", count)
// delete row manually via Exec
_, err = dbmap.Exec("delete from posts where post_id=?", p2.Id)
checkErr(err, "Exec failed")
// confirm count is zero
count, err = dbmap.SelectInt("select count(*) from posts")
checkErr(err, "select count(*) failed")
log.Println("Row count - should be zero:", count)
log.Println("Done!")
}
type Post struct {
// db tag lets you specify the column name if it differs from the struct field
Id int64 `db:"post_id"`
Created int64
Title string `db:",size:50"` // Column size set to 50
Body string `db:"article_body,size:1024"` // Set both column name and size
}
func newPost(title, body string) Post {
return Post{
Created: time.Now().UnixNano(),
Title: title,
Body: body,
}
}
func initDb() *gorp.DbMap {
// connect to db using standard Go database/sql API
// use whatever database/sql driver you wish
db, err := sql.Open("sqlite3", "/tmp/post_db.bin")
checkErr(err, "sql.Open failed")
// construct a gorp DbMap
dbmap := &gorp.DbMap{Db: db, Dialect: gorp.SqliteDialect{}}
// add a table, setting the table name to 'posts' and
// specifying that the Id property is an auto incrementing PK
dbmap.AddTableWithName(Post{}, "posts").SetKeys(true, "Id")
// create the table. in a production system you'd generally
// use a migration tool, or create the tables via scripts
err = dbmap.CreateTablesIfNotExists()
checkErr(err, "Create tables failed")
return dbmap
}
func checkErr(err error, msg string) {
if err != nil {
log.Fatalln(msg, err)
}
} ExamplesMapping structs to tablesFirst define some types: type Invoice struct {
Id int64
Created int64
Updated int64
Memo string
PersonId int64
}
type Person struct {
Id int64
Created int64
Updated int64
FName string
LName string
}
// Example of using tags to alias fields to column names
// The 'db' value is the column name
//
// A hyphen will cause gorp to skip this field, similar to the
// Go json package.
//
// This is equivalent to using the ColMap methods:
//
// table := dbmap.AddTableWithName(Product{}, "product")
// table.ColMap("Id").Rename("product_id")
// table.ColMap("Price").Rename("unit_price")
// table.ColMap("IgnoreMe").SetTransient(true)
//
// You can optionally declare the field to be a primary key and/or autoincrement
//
type Product struct {
Id int64 `db:"product_id, primarykey, autoincrement"`
Price int64 `db:"unit_price"`
IgnoreMe string `db:"-"`
} Then create a mapper, typically you'd do this one time at app startup: // connect to db using standard Go database/sql API
// use whatever database/sql driver you wish
db, err := sql.Open("mymysql", "tcp:localhost:3306*mydb/myuser/mypassword")
// construct a gorp DbMap
dbmap := &gorp.DbMap{Db: db, Dialect: gorp.MySQLDialect{"InnoDB", "UTF8"}}
// register the structs you wish to use with gorp
// you can also use the shorter dbmap.AddTable() if you
// don't want to override the table name
//
// SetKeys(true) means we have a auto increment primary key, which
// will get automatically bound to your struct post-insert
//
t1 := dbmap.AddTableWithName(Invoice{}, "invoice_test").SetKeys(true, "Id")
t2 := dbmap.AddTableWithName(Person{}, "person_test").SetKeys(true, "Id")
t3 := dbmap.AddTableWithName(Product{}, "product_test").SetKeys(true, "Id") Struct Embeddinggorp supports embedding structs. For example: type Names struct {
FirstName string
LastName string
}
type WithEmbeddedStruct struct {
Id int64
Names
}
es := &WithEmbeddedStruct{-1, Names{FirstName: "Alice", LastName: "Smith"}}
err := dbmap.Insert(es) See the Create/Drop TablesAutomatically create / drop registered tables. This is useful for unit tests but is entirely optional. You can of course use gorp with tables created manually, or with a separate migration tool (like sql-migrate, goose or migrate). // create all registered tables
dbmap.CreateTables()
// same as above, but uses "if not exists" clause to skip tables that are
// already defined
dbmap.CreateTablesIfNotExists()
// drop
dbmap.DropTables() SQL LoggingOptionally you can pass in a logger to trace all SQL statements. I recommend enabling this initially while you're getting the feel for what gorp is doing on your behalf. Gorp defines a // Will log all SQL statements + args as they are run
// The first arg is a string prefix to prepend to all log messages
dbmap.TraceOn("[gorp]", log.New(os.Stdout, "myapp:", log.Lmicroseconds))
// Turn off tracing
dbmap.TraceOff() Insert// Must declare as pointers so optional callback hooks
// can operate on your data, not copies
inv1 := &Invoice{0, 100, 200, "first order", 0}
inv2 := &Invoice{0, 100, 200, "second order", 0}
// Insert your rows
err := dbmap.Insert(inv1, inv2)
// Because we called SetKeys(true) on Invoice, the Id field
// will be populated after the Insert() automatically
fmt.Printf("inv1.Id=%d inv2.Id=%d\n", inv1.Id, inv2.Id) UpdateContinuing the above example, use the // count is the # of rows updated, which should be 1 in this example
count, err := dbmap.Update(inv1) DeleteIf you have primary key(s) defined for a struct, you can use the count, err := dbmap.Delete(inv1) Select by KeyUse the // fetch Invoice with Id=99
obj, err := dbmap.Get(Invoice{}, 99)
inv := obj.(*Invoice) Ad Hoc SQLSELECT
// Select a slice - first return value is not needed when a slice pointer is passed to Select()
var posts []Post
_, err := dbmap.Select(&posts, "select * from post order by id")
// You can also use primitive types
var ids []string
_, err := dbmap.Select(&ids, "select id from post")
// Select a single row.
// Returns an error if no row found, or if more than one row is found
var post Post
err := dbmap.SelectOne(&post, "select * from post where id=?", id) Want to do joins? Just write the SQL and the struct. gorp will bind them: // Define a type for your join
// It *must* contain all the columns in your SELECT statement
//
// The names here should match the aliased column names you specify
// in your SQL - no additional binding work required. simple.
//
type InvoicePersonView struct {
InvoiceId int64
PersonId int64
Memo string
FName string
}
// Create some rows
p1 := &Person{0, 0, 0, "bob", "smith"}
err = dbmap.Insert(p1)
checkErr(err, "Insert failed")
// notice how we can wire up p1.Id to the invoice easily
inv1 := &Invoice{0, 0, 0, "xmas order", p1.Id}
err = dbmap.Insert(inv1)
checkErr(err, "Insert failed")
// Run your query
query := "select i.Id InvoiceId, p.Id PersonId, i.Memo, p.FName " +
"from invoice_test i, person_test p " +
"where i.PersonId = p.Id"
// pass a slice to Select()
var list []InvoicePersonView
_, err := dbmap.Select(&list, query)
// this should test true
expected := InvoicePersonView{inv1.Id, p1.Id, inv1.Memo, p1.FName}
if reflect.DeepEqual(list[0], expected) {
fmt.Println("Woot! My join worked!")
} SELECT string or int64gorp provides a few convenience methods for selecting a single string or int64. // select single int64 from db (use $1 instead of ? for postgresql)
i64, err := dbmap.SelectInt("select count(*) from foo where blah=?", blahVal)
// select single string from db:
s, err := dbmap.SelectStr("select name from foo where blah=?", blahVal) Named bind parametersYou may use a map or struct to bind parameters by name. This is currently only supported in SELECT queries. _, err := dbm.Select(&dest, "select * from Foo where name = :name and age = :age", map[string]interface{}{
"name": "Rob",
"age": 31,
}) UPDATE / DELETEYou can execute raw SQL if you wish. Particularly good for batch operations. res, err := dbmap.Exec("delete from invoice_test where PersonId=?", 10) TransactionsYou can batch operations into a transaction: func InsertInv(dbmap *DbMap, inv *Invoice, per *Person) error {
// Start a new transaction
trans, err := dbmap.Begin()
if err != nil {
return err
}
err = trans.Insert(per)
checkErr(err, "Insert failed")
inv.PersonId = per.Id
err = trans.Insert(inv)
checkErr(err, "Insert failed")
// if the commit is successful, a nil error is returned
return trans.Commit()
} |
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