(ns my-app.core
(:require [chrondb.core :as chrondb]))
;; Create with default configuration (in-memory database)
(def db (chrondb/create-chrondb))
;; Create with custom configuration
(def config {:git {:committer-name "My App"
:committer-email "app@example.com"}
:storage {:data-dir "/path/to/storage"}})
(def db (chrondb/create-chrondb config))
CRUD Operations
;; Create/Update documents
(chrondb/save db "user:1" {:name "Alice"
:email "alice@example.com"
:roles ["admin"]})
(chrondb/save db "user:2" {:name "Bob"
:email "bob@example.com"
:roles ["user"]})
;; Read a document
(def user (chrondb/get db "user:1"))
(println user) ;; => {:name "Alice", :email "alice@example.com", :roles ["admin"]}
;; Update a document (merge with existing data)
(chrondb/save db "user:1" (assoc user :age 30))
;; Delete a document
(chrondb/delete db "user:2")
(println (chrondb/get db "user:2")) ;; => nil
Searching
ChronDB uses Lucene for powerful search capabilities:
;; Basic search by field
(def results (chrondb/search db "name:Alice"))
;; Search with multiple conditions
(def results (chrondb/search db "name:Alice AND age:[25 TO 35]"))
;; Wildcard search
(def results (chrondb/search db "email:*@example.com"))
;; Search with paging
(def page1 (chrondb/search db "roles:admin" {:limit 10 :offset 0}))
(def page2 (chrondb/search db "roles:admin" {:limit 10 :offset 10}))
Version Control Features
Working with Document History
;; Get the history of a document
(def history (chrondb/history db "user:1"))
(println history)
;; => [{:timestamp "2023-05-10T14:30:00Z"
;; :data {:name "Alice" :email "alice@example.com" :roles ["admin"]}}
;; {:timestamp "2023-05-11T09:15:00Z"
;; :data {:name "Alice" :email "alice@example.com" :roles ["admin"] :age 30}}]
;; Get a document at a specific point in time
(def old-version (chrondb/get-at db "user:1" "2023-05-10T14:30:00Z"))
(println old-version) ;; => Version without :age field
;; Compare document versions
(def diff (chrondb/diff db "user:1" "2023-05-10T14:30:00Z" "2023-05-11T09:15:00Z"))
(println diff) ;; => Shows what changed between versions
Working with Branches
;; Create a new branch for testing
(def test-db (chrondb/create-branch db "test"))
;; Make changes in the test branch
(chrondb/save test-db "user:1" {:name "Alice (Test)"
:email "alice.test@example.com"})
;; The changes are isolated to the test branch
(println (chrondb/get db "user:1")) ;; => Original version
(println (chrondb/get test-db "user:1")) ;; => Modified version
;; Switch the current database to a different branch
(def switched-db (chrondb/switch-branch db "test"))
;; Merge changes from one branch to another
(def merged-db (chrondb/merge-branch db "test" "main"))
Transactions
ChronDB supports atomic transactions:
;; Execute multiple operations atomically
(chrondb/with-transaction [db]
(chrondb/save db "order:1" {:items [{:id "item1" :qty 2}]
:total 50.0
:status "pending"})
;; Update inventory
(let [inventory (chrondb/get db "inventory:item1")]
(chrondb/save db "inventory:item1"
(update inventory :stock - 2)))
;; Update user orders
(let [user (chrondb/get db "user:1")]
(chrondb/save db "user:1"
(update user :orders conj "order:1"))))
;; If any operation fails, all changes are rolled back
Advanced Features
Custom Hooks
;; Register a pre-save hook for validation
(chrondb/register-hook db :pre-save
(fn [doc]
(when (and (contains? doc :email)
(not (re-matches #".*@.*\..+" (:email doc))))
(throw (ex-info "Invalid email format" {:doc doc})))
doc))
;; Register a post-save hook for notifications
(chrondb/register-hook db :post-save
(fn [doc]
(println "Document saved:" doc)
doc))
Database Statistics and Maintenance
;; Get database statistics
(def stats (chrondb/stats db))
(println stats)
;; => {:documents 100, :branches 2, :size "10MB", ...}
;; Perform database health check
(def health (chrondb/health-check db))
(println health)
;; => {:status "healthy", :issues []}
;; Create a backup
(chrondb/backup db "/path/to/backup.tar.gz")
