level-db golang implementation writing over existing values?

huangapple
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英文:

level-db golang implementation writing over existing values?

问题

我正在尝试使用leveldb-g实现，并遇到一些问题。

这是我的实现（基于这里的另一个答案here）：

  1. package propertyData
  3. import (
  4. 	"code.google.com/p/leveldb-go/leveldb/db"
  5. 	"code.google.com/p/leveldb-go/leveldb/table"
  6. 	"log"
  7. 	"runtime"
  8. )
  10. const (
  11. 	DBFILE = "./admin.db"
  12. )
  14. var DBFS = db.DefaultFileSystem
  16. func AddDataToProperty(property, value string) {
  17. 	Connection, e := DBFS.Create(DBFILE)
  18. 	Check(e)
  19. 	w := table.NewWriter(Connection, nil)
  20. 	defer w.Close()
  22. 	e = w.Set([]byte(property), []byte(value), nil)
  23. }
  25. func GetDataFromProperty(property string) string {
  27. 	v := findOne([]byte(property))
  29. 	return string(v)
  30. }
  32. func findOne(k []byte) []byte {
  33. 	Connection, e := DBFS.Open(DBFILE)
  34. 	Check(e)
  35. 	r := table.NewReader(Connection, nil)
  36. 	v1, err := r.Get([]byte(k), nil)
  37. 	if err != nil {
  38. 		log.Fatalf("An error occurred finding one", err.Error())
  39. 	}
  41. 	return v1
  43. }
  45. func Check(e error) {
  46. 	if e != nil {
  47. 		_, file, line, _ := runtime.Caller(1)
  48. 		log.Fatalf("Bad Happened: %s, %s", file, line)
  49. 	}
  50. }

以及一个测试：

  1. package propertyData
  3. import (
  4. 	"com.levelsbeyond/admin/propertyData"
  5. 	"log"
  6. 	"os"
  7. 	"testing"
  8. )
  10. func TestAddProperty(t *testing.T) {
  11. 	os.RemoveAll("./admin.db")
  13. 	propertyData.AddDataToProperty("test.property", "one")
  14. 	propertyData.AddDataToProperty("test.property", "two")
  15. 	propertyData.AddDataToProperty("test.property", "three")
  17. 	propertyValue := propertyData.GetDataFromProperty("test.property")
  18. 	log.Println(propertyValue)
  20. 	propertyData.AddDataToProperty("test.different", "four")
  21. 	propertyValue = propertyData.GetDataFromProperty("test.different")
  22. 	log.Println(propertyValue)
  24. 	propertyValue = propertyData.GetDataFromProperty("test.property")
  25. 	log.Println(propertyValue)
  27. }

输出结果为：

  1. === RUN TestAddProperty
  2. 2013/09/16 10:47:50 three
  3. 2013/09/16 10:47:50 four
  4. 2013/09/16 10:47:50 
  5. --- PASS: TestAddProperty (0.00 seconds)

好像写入第二个属性（"property.different"）会覆盖我已经存在的值。我确定我做了一些愚蠢的事情，非常感谢任何帮助。

编辑

我在findOne函数中添加了一些错误处理（感谢 @miltonb），实际上在那里遇到了一个错误，尽管我不确定该如何处理：

  1. === RUN TestAddProperty
  2. 2013/09/16 15:36:34 three
  3. 2013/09/16 15:36:34 four
  4. 2013/09/16 15:36:34 An error occurred finding one%!(EXTRA string=leveldb/db: not found)
  5. exit status 1
  6. FAIL	command-line-arguments	0.018s
英文:

I am trying to use the leveldb-g implementation and having some issues.

Here is my implementaation (based on another answer here

  1. package propertyData
  3. import (
  4. 	"code.google.com/p/leveldb-go/leveldb/db"
  5. 	"code.google.com/p/leveldb-go/leveldb/table"
  6. 	"log"
  7. 	"runtime"
  8. )
  10. const (
  11. 	DBFILE = "./admin.db"
  12. )
  14. var DBFS = db.DefaultFileSystem
  16. func AddDataToProperty(property, value string) {
  17. 	Connection, e := DBFS.Create(DBFILE)
  18. 	Check(e)
  19. 	w := table.NewWriter(Connection, nil)
  20. 	defer w.Close()
  22. 	e = w.Set([]byte(property), []byte(value), nil)
  23. }
  25. func GetDataFromProperty(property string) string {
  27. 	v := findOne([]byte(property))
  29. 	return string(v)
  30. }
  32. func findOne(k []byte) []byte {
  33. 	Connection, e := DBFS.Open(DBFILE)
  34. 	Check(e)
  35. 	r := table.NewReader(Connection, nil)
  36. 	v1, err := r.Get([]byte(k), nil)
  37. 	if err != nil {
  38. 		log.Fatalf("An error occurred finding one", err.Error())
  39. 	}
  41. 	return v1
  43. }
  45. func Check(e error) {
  46. 	if e != nil {
  47. 		_, file, line, _ := runtime.Caller(1)
  48. 		log.Fatalf("Bad Happened: %s, %s", file, line)
  49. 	}
  50. }

and a test:

  1. package propertyData
  3. import (
  4. 	"com.levelsbeyond/admin/propertyData"
  5. 	"log"
  6. 	"os"
  7. 	"testing"
  8. )
  10. func TestAddProperty(t *testing.T) {
  11. 	os.RemoveAll("./admin.db")
  13. 	propertyData.AddDataToProperty("test.property", "one")
  14. 	propertyData.AddDataToProperty("test.property", "two")
  15. 	propertyData.AddDataToProperty("test.property", "three")
  17. 	propertyValue := propertyData.GetDataFromProperty("test.property")
  18. 	log.Println(propertyValue)
  20. 	propertyData.AddDataToProperty("test.different", "four")
  21. 	propertyValue = propertyData.GetDataFromProperty("test.different")
  22. 	log.Println(propertyValue)
  24. 	propertyValue = propertyData.GetDataFromProperty("test.property")
  25. 	log.Println(propertyValue)
  27. }

Which outputs:

  1. === RUN TestAddProperty
  2. 2013/09/16 10:47:50 three
  3. 2013/09/16 10:47:50 four
  4. 2013/09/16 10:47:50 
  5. --- PASS: TestAddProperty (0.00 seconds)

It's like writing the second property ("property.different") Overwrites the values I already have in there. I'm sure I'm doing something dumb, any help would be greatly appreciated.

EDIT

I added some error handling in the findOne function (thanks @miltonb) and I actually am getting an error there, though I'm not sure what to make of it:

  1. === RUN TestAddProperty
  2. 2013/09/16 15:36:34 three
  3. 2013/09/16 15:36:34 four
  4. 2013/09/16 15:36:34 An error occurred finding one%!(EXTRA string=leveldb/db: not found)
  5. exit status 1
  6. FAIL	command-line-arguments	0.018s

答案1

得分: 2

将切换到另一个实现leveldb的版本，该版本似乎有更好的文档，例如levidb（http://godoc.org/github.com/jmhodges/levigo）。

英文:

Change to another implementation of leveldb with what looks to be better documentation such as levidb http://godoc.org/github.com/jmhodges/levigo.

huangapple
  • 本文由 发表于 2013年9月17日 00:51:14
  • 转载请务必保留本文链接：https://go.coder-hub.com/18833310.html
  • go
  • leveldb
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