mirror of https://github.com/tidwall/buntdb.git
Added AscendEqual and DescendEqual
AscendEqual and DescendEqual return only the items that equal a specified value. Closes #26
This commit is contained in:
Josh Baker
parent
83418750ee
commit
b67b1b8c16
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@ -148,7 +148,9 @@ err := tx.Ascend("", func(key, value string) bool{
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})
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```
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There is also `AscendGreaterOrEqual`, `AscendLessThan`, `AscendRange`, `Descend`, `DescendLessOrEqual`, `DescendGreaterThan`, and `DescendRange`. Please see the [documentation](https://godoc.org/github.com/tidwall/buntdb) for more information on these functions.
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There is also `AscendGreaterOrEqual`, `AscendLessThan`, `AscendRange`, `AscendEqual`, `Descend`, `DescendLessOrEqual`, `DescendGreaterThan`, `DescendRange`, and `DescendEqual`. Please see the [documentation](https://godoc.org/github.com/tidwall/buntdb) for more information on these functions.
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## Custom Indexes
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66
buntdb.go
66
buntdb.go
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@ -1185,6 +1185,7 @@ type dbItemOpts struct {
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type dbItem struct {
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key, val string // the binary key and value
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opts *dbItemOpts // optional meta information
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keyless bool // keyless item for scanning
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}
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func appendArray(buf []byte, count int) []byte {
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@ -1278,6 +1279,11 @@ func (dbi *dbItem) Less(item btree.Item, ctx interface{}) bool {
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}
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}
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// Always fall back to the key comparison. This creates absolute uniqueness.
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if dbi.keyless {
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return false
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} else if dbi2.keyless {
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return true
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}
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return dbi.key < dbi2.key
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}
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@ -1507,6 +1513,10 @@ func (tx *Tx) scan(desc, gt, lt bool, index, start, stop string,
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} else {
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itemA = &dbItem{val: start}
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itemB = &dbItem{val: stop}
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if desc {
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itemA.keyless = true
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itemB.keyless = true
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}
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}
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}
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// execute the scan on the underlying tree.
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@ -1709,6 +1719,62 @@ func (tx *Tx) DescendRange(index, lessOrEqual, greaterThan string,
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)
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}
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// AscendEqual calls the iterator for every item in the database that equals
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// pivot, until iterator returns false.
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// When an index is provided, the results will be ordered by the item values
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// as specified by the less() function of the defined index.
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// When an index is not provided, the results will be ordered by the item key.
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// An invalid index will return an error.
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func (tx *Tx) AscendEqual(index, pivot string,
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iterator func(key, value string) bool) error {
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var err error
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var less func(a, b string) bool
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if index != "" {
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less, err = tx.GetLess(index)
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if err != nil {
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return err
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}
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}
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return tx.AscendGreaterOrEqual(index, pivot, func(key, value string) bool {
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if less == nil {
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if key != pivot {
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return false
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}
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} else if less(pivot, value) {
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return false
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}
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return iterator(key, value)
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})
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}
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// DescendEqual calls the iterator for every item in the database that equals
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// pivot, until iterator returns false.
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// When an index is provided, the results will be ordered by the item values
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// as specified by the less() function of the defined index.
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// When an index is not provided, the results will be ordered by the item key.
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// An invalid index will return an error.
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func (tx *Tx) DescendEqual(index, pivot string,
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iterator func(key, value string) bool) error {
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var err error
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var less func(a, b string) bool
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if index != "" {
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less, err = tx.GetLess(index)
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if err != nil {
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return err
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}
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}
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return tx.DescendLessOrEqual(index, pivot, func(key, value string) bool {
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if less == nil {
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if key != pivot {
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return false
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}
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} else if less(value, pivot) {
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return false
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}
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return iterator(key, value)
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})
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}
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// rect is used by Intersects
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type rect struct {
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min, max []float64
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104
buntdb_test.go
104
buntdb_test.go
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@ -495,6 +495,110 @@ func TestDeleteAll(t *testing.T) {
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}
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}
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func TestAscendEqual(t *testing.T) {
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db := testOpen(t)
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defer testClose(db)
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if err := db.Update(func(tx *Tx) error {
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for i := 0; i < 300; i++ {
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_, _, err := tx.Set(fmt.Sprintf("key:%05dA", i), fmt.Sprintf("%d", i+1000), nil)
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if err != nil {
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return err
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}
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_, _, err = tx.Set(fmt.Sprintf("key:%05dB", i), fmt.Sprintf("%d", i+1000), nil)
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if err != nil {
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return err
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}
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}
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return tx.CreateIndex("num", "*", IndexInt)
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}); err != nil {
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t.Fatal(err)
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}
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var res []string
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if err := db.View(func(tx *Tx) error {
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return tx.AscendEqual("", "key:00055A", func(key, value string) bool {
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res = append(res, key)
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return true
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})
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}); err != nil {
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t.Fatal(err)
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}
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if len(res) != 1 {
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t.Fatalf("expected %v, got %v", 1, len(res))
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}
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if res[0] != "key:00055A" {
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t.Fatalf("expected %v, got %v", "key:00055A", res[0])
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}
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res = nil
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if err := db.View(func(tx *Tx) error {
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return tx.AscendEqual("num", "1125", func(key, value string) bool {
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res = append(res, key)
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return true
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})
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}); err != nil {
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t.Fatal(err)
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}
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if len(res) != 2 {
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t.Fatalf("expected %v, got %v", 2, len(res))
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}
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if res[0] != "key:00125A" {
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t.Fatalf("expected %v, got %v", "key:00125A", res[0])
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}
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if res[1] != "key:00125B" {
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t.Fatalf("expected %v, got %v", "key:00125B", res[1])
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}
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}
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func TestDescendEqual(t *testing.T) {
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db := testOpen(t)
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defer testClose(db)
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if err := db.Update(func(tx *Tx) error {
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for i := 0; i < 300; i++ {
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_, _, err := tx.Set(fmt.Sprintf("key:%05dA", i), fmt.Sprintf("%d", i+1000), nil)
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if err != nil {
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return err
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}
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_, _, err = tx.Set(fmt.Sprintf("key:%05dB", i), fmt.Sprintf("%d", i+1000), nil)
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if err != nil {
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return err
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}
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}
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return tx.CreateIndex("num", "*", IndexInt)
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}); err != nil {
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t.Fatal(err)
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}
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var res []string
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if err := db.View(func(tx *Tx) error {
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return tx.DescendEqual("", "key:00055A", func(key, value string) bool {
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res = append(res, key)
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return true
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})
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}); err != nil {
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t.Fatal(err)
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}
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if len(res) != 1 {
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t.Fatalf("expected %v, got %v", 1, len(res))
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}
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if res[0] != "key:00055A" {
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t.Fatalf("expected %v, got %v", "key:00055A", res[0])
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}
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res = nil
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if err := db.View(func(tx *Tx) error {
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return tx.DescendEqual("num", "1125", func(key, value string) bool {
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res = append(res, key)
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return true
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})
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}); err != nil {
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t.Fatal(err)
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}
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if len(res) != 2 {
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t.Fatalf("expected %v, got %v", 2, len(res))
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}
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if res[0] != "key:00125B" {
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t.Fatalf("expected %v, got %v", "key:00125B", res[0])
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}
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if res[1] != "key:00125A" {
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t.Fatalf("expected %v, got %v", "key:00125A", res[1])
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}
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}
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func TestVariousTx(t *testing.T) {
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db := testOpen(t)
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defer testClose(db)
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