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POC: golang database/sql, row to map[string]interface{} mapping
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package main | |
import ( | |
"database/sql" | |
"database/sql/driver" | |
"fmt" | |
"strings" | |
) | |
type Mapper interface { | |
sql.Scanner | |
} | |
type MetaHolder struct { | |
Values map[string]interface{} | |
} | |
type MapMapper struct { | |
Value map[string]interface{} | |
} | |
func (self *MapMapper) Scan(src interface{}) error { | |
if holder, ok := src.(*MetaHolder); ok { | |
self.Value = holder.Values | |
return nil | |
} else { | |
return fmt.Errorf("Scan error, unsupported %#v", src) | |
} | |
} | |
type delegator struct { | |
} | |
func (self *delegator) Open(name string) (driver.Conn, error) { | |
sects := strings.SplitN(name, ":", 2) | |
db, err := sql.Open(sects[0], sects[1]) | |
if err != nil { | |
return nil, err | |
} | |
defer db.Close() | |
conn, err := db.Driver().Open(sects[1]) | |
if err != nil { | |
return conn, err | |
} | |
return &dconn{delegate: conn}, nil | |
} | |
type dconn struct { | |
delegate driver.Conn | |
} | |
func (self *dconn) Begin() (driver.Tx, error) { | |
return self.delegate.Begin() | |
} | |
func (self *dconn) Close() error { | |
return self.delegate.Close() | |
} | |
func (self *dconn) Prepare(query string) (driver.Stmt, error) { | |
stmt, err := self.delegate.Prepare(query) | |
if err != nil { | |
return stmt, err | |
} | |
return &dstmt{delegate: stmt}, nil | |
} | |
type dstmt struct { | |
delegate driver.Stmt | |
} | |
func (self *dstmt) Exec(args []driver.Value) (driver.Result, error) { | |
return self.delegate.Exec(args) | |
} | |
func (self *dstmt) Query(args []driver.Value) (driver.Rows, error) { | |
rows, err := self.delegate.Query(args) | |
if err != nil { | |
return rows, err | |
} | |
return &drows{delegate: rows}, nil | |
} | |
func (self *dstmt) NumInput() int { | |
return self.delegate.NumInput() | |
} | |
func (self *dstmt) Close() error { | |
return self.delegate.Close() | |
} | |
type drows struct { | |
delegate driver.Rows | |
} | |
func (self *drows) Columns() []string { | |
return []string{""} | |
} | |
func (self *drows) Next(dest []driver.Value) error { | |
columns := self.delegate.Columns() | |
values := make([]driver.Value, len(columns)) | |
err := self.delegate.Next(values) | |
if err != nil { | |
return err | |
} | |
holder := &MetaHolder{ | |
Values: make(map[string]interface{}), | |
} | |
for i, column := range columns { | |
holder.Values[column] = values[i] | |
} | |
dest[0] = holder | |
return nil | |
} | |
func (self *drows) Close() error { | |
return self.delegate.Close() | |
} | |
func init() { | |
sql.Register("poc", &delegator{}) | |
} |
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package main | |
import ( | |
"database/sql" | |
"log" | |
"os" | |
"time" | |
_ "github.com/lib/pq" | |
) | |
func exec() int { | |
db, err := sql.Open("poc", "postgres:user=postgres password=postgres dbname=golang sslmode=disable") | |
if err != nil { | |
log.Printf("Failed to open database: %s\n", err) | |
return 1 | |
} | |
defer db.Close() | |
started := time.Now() | |
row := new(MapMapper) | |
err = db.QueryRow("select * from information_schema.tables").Scan(row) | |
if err != nil { | |
log.Printf("Failed to query: %s\n", err) | |
return 1 | |
} | |
ended := time.Now() | |
log.Printf("%#v\n", row.Value) | |
log.Printf("time required: %s\n", ended.Sub(started).String()) | |
return 0 | |
} | |
func main() { | |
os.Exit(exec()) | |
} |
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