Implement an in-memory databasewqa

pkg/ramdb/tables.go

@@ -0,0 +1,45 @@
+package ramdb
+
+import (
+	"sync"
+
+	"github.com/google/btree"
+)
+
+type table struct {
+	exists  bool
+	mutex   *sync.Mutex
+	indexes map[string]*index
+}
+
+// CreateIndex creates an index for onColumn.
+func (t *table) CreateIndex(column string) error {
+	if column == "" {
+		return ErrInvalidIndex
+	}
+
+	if _, found := t.indexes[column]; found {
+		return ErrIndexExists
+	}
+
+	idx := &index{
+		tree:   btree.New(5),
+		column: column,
+		table:  t,
+	}
+
+	t.mutex.Lock()
+	defer t.mutex.Unlock()
+
+	t.indexes[column] = idx
+	return nil
+}
+
+// HasIndex returns true if an index exists for the column and false if it does not.
+func (t *table) HasIndex(column string) bool {
+	if _, found := t.indexes[column]; found {
+		return true
+	}
+
+	return false
+}