[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"me":3,"catalog:en:database\u002Ftransactions-isolation":4,"config":214},null,{"field_key":5,"field_name":6,"seniority":7,"topic_key":8,"topic_name":9,"spec_key":7,"spec_name":7,"locale":10,"cell_total":11,"field_total":12,"seniorities":13,"topics":17,"specs":115,"samples":129},"database","Database","","transactions-isolation","Transactions Isolation","en",75,2475,[14,15,16],"junior","mid","senior",[18,21,24,27,30,33,36,39,42,45,48,51,54,57,60,63,66,69,72,75,78,81,84,87,90,93,96,99,102,105,108,111,114],{"key":19,"name":20,"count":11},"backup-recovery","Backup Recovery",{"key":22,"name":23,"count":11},"data-modeling","Data Modeling",{"key":25,"name":26,"count":11},"indexing","Indexing",{"key":28,"name":29,"count":11},"mongodb-aggregation","Mongodb Aggregation",{"key":31,"name":32,"count":11},"mongodb-indexes-queries","Mongodb Indexes Queries",{"key":34,"name":35,"count":11},"mongodb-operations","Mongodb Operations",{"key":37,"name":38,"count":11},"mongodb-replication-sharding","Mongodb Replication Sharding",{"key":40,"name":41,"count":11},"mongodb-schema-modeling","Mongodb Schema Modeling",{"key":43,"name":44,"count":11},"mongodb-transactions-consistency","Mongodb Transactions Consistency",{"key":46,"name":47,"count":11},"mysql-indexes","Mysql Indexes",{"key":49,"name":50,"count":11},"mysql-innodb-transactions","Mysql Innodb Transactions",{"key":52,"name":53,"count":11},"mysql-operations","Mysql Operations",{"key":55,"name":56,"count":11},"mysql-query-optimization","Mysql Query Optimization",{"key":58,"name":59,"count":11},"mysql-replication-scaling","Mysql Replication Scaling",{"key":61,"name":62,"count":11},"mysql-types-constraints","Mysql Types Constraints",{"key":64,"name":65,"count":11},"nosql-models","Nosql Models",{"key":67,"name":68,"count":11},"performance-tuning","Performance Tuning",{"key":70,"name":71,"count":11},"pg-indexes","Pg Indexes",{"key":73,"name":74,"count":11},"pg-mvcc-vacuum","Pg Mvcc Vacuum",{"key":76,"name":77,"count":11},"pg-operations","Pg Operations",{"key":79,"name":80,"count":11},"pg-query-planning","Pg Query Planning",{"key":82,"name":83,"count":11},"pg-transactions-locking","Pg Transactions Locking",{"key":85,"name":86,"count":11},"pg-types-constraints","Pg Types Constraints",{"key":88,"name":89,"count":11},"query-optimization","Query Optimization",{"key":91,"name":92,"count":11},"redis-cluster-sharding","Redis Cluster Sharding",{"key":94,"name":95,"count":11},"redis-data-structures","Redis Data Structures",{"key":97,"name":98,"count":11},"redis-expiration-eviction","Redis Expiration Eviction",{"key":100,"name":101,"count":11},"redis-persistence","Redis Persistence",{"key":103,"name":104,"count":11},"redis-replication-sentinel","Redis Replication Sentinel",{"key":106,"name":107,"count":11},"redis-transactions-scripting","Redis Transactions Scripting",{"key":109,"name":110,"count":11},"replication-scaling","Replication Scaling",{"key":112,"name":113,"count":11},"security-access","Security Access",{"key":8,"name":9,"count":11},[116,120,123,126],{"key":117,"name":118,"count":119},"mongodb","MongoDB",450,{"key":121,"name":122,"count":119},"mysql","MySQL",{"key":124,"name":125,"count":119},"postgresql","PostgreSQL",{"key":127,"name":128,"count":119},"redis","Redis",[130,148,161,175,188,201],{"id":131,"topic":9,"difficulty":132,"body":133,"options":134,"correct_key":139,"explanation":147},"019f56bb-b6fd-7694-b2aa-bb6134d8994c",1,"In the ACID acronym, what does **Atomicity** guarantee about a transaction?",[135,138,141,144],{"key":136,"text":137},"a","Its changes survive a crash once it has committed",{"key":139,"text":140},"b","All of its statements take effect together, or none of them do",{"key":142,"text":143},"c","Concurrent transactions cannot see each other's uncommitted changes",{"key":145,"text":146},"d","It moves the database from one valid state to another valid state","Atomicity is the all-or-nothing property: a transaction's operations either all commit or all roll back. Option (a) is Durability, (c) is Isolation, and (d) is Consistency — the other three ACID letters, each of which addresses a different concern.",{"id":149,"topic":9,"difficulty":132,"body":150,"options":151,"correct_key":145,"explanation":160},"019f56bb-b6fe-7607-8a77-8c7e4a1f25b1","In the ACID acronym, what does **Durability** guarantee?",[152,154,156,158],{"key":136,"text":153},"A transaction sees a consistent snapshot for its entire duration",{"key":139,"text":155},"Each transaction behaves as if it were the only one running",{"key":142,"text":157},"A transaction either completes fully or is rolled back with no effect",{"key":145,"text":159},"After a transaction commits, its changes survive a later system crash","Durability means committed data is not lost, even on power failure or crash — engines achieve this by flushing a write-ahead log to durable storage before acknowledging the commit. Option (c) describes Atomicity, and (a)\u002F(b) describe aspects of Isolation.",{"id":162,"topic":9,"difficulty":163,"body":164,"options":165,"correct_key":136,"explanation":174},"019f56bb-b6ff-723c-851a-43ee40bdf101",2,"What does the **Isolation** property in ACID primarily address?",[166,168,170,172],{"key":136,"text":167},"Keeping concurrent transactions from seeing each other's incomplete work",{"key":139,"text":169},"Recovering already-committed data after a power failure",{"key":142,"text":171},"Validating each row against CHECK and foreign-key constraints",{"key":145,"text":173},"Splitting a large transaction into smaller units that commit on their own","Isolation governs how concurrent transactions are prevented from interfering — ideally each behaves as if it ran alone. Recovering committed data (b) is Durability, and constraint validation (c) belongs to Consistency; (d) contradicts atomicity rather than describing isolation.",{"id":176,"topic":9,"difficulty":163,"body":177,"options":178,"correct_key":142,"explanation":187},"019f56bb-b6ff-7b35-9d8c-9b0589c707fc","In ACID, the **Consistency** property means that a transaction...",[179,181,183,185],{"key":136,"text":180},"...always reads the most recently committed value written by any other open session",{"key":139,"text":182},"...holds all of its locks until every other transaction has finished",{"key":142,"text":184},"...moves the database from one valid state to another, preserving its constraints",{"key":145,"text":186},"...runs faster when fewer other transactions are active","Consistency means every committed transaction leaves the database satisfying all its rules (constraints, cascades, triggers) — it never lands in an invalid state. Option (a) describes read visibility (an isolation concern), and (b)\u002F(d) are unrelated to the ACID Consistency guarantee.",{"id":189,"topic":9,"difficulty":132,"body":190,"options":191,"correct_key":139,"explanation":200},"019f56bb-b700-73ef-8b0c-850cc50cbfb6","```sql\nBEGIN;\nUPDATE accounts SET balance = balance - 100 WHERE id = 1;\nROLLBACK;\n```\nAfter this runs, what is account 1's balance?",[192,194,196,198],{"key":136,"text":193},"Reduced by 100 — the UPDATE already wrote the new value to the row",{"key":139,"text":195},"Unchanged — ROLLBACK undoes the UPDATE made inside the transaction",{"key":142,"text":197},"Reduced by 100 until a later COMMIT is issued to overwrite it",{"key":145,"text":199},"NULL — ROLLBACK clears every column the transaction touched","ROLLBACK discards every change made since BEGIN, so the balance returns to its pre-transaction value as if the UPDATE never happened. The UPDATE's effect was only visible inside the open transaction (a is wrong), and a rollback restores old values rather than nulling columns (d is wrong).",{"id":202,"topic":9,"difficulty":163,"body":203,"options":204,"correct_key":136,"explanation":213},"019f56bb-b701-7254-9c0b-1f81f2ea4e72","An order-placement routine inserts one row into `orders`, one row into `order_items`, then decrements `products.stock`. Why should these three statements run inside a single transaction?",[205,207,209,211],{"key":136,"text":206},"So a partial failure cannot leave orders without their items or wrong stock",{"key":139,"text":208},"So each statement is automatically retried until it eventually succeeds",{"key":142,"text":210},"So the three statements are executed in parallel and finish faster",{"key":145,"text":212},"So the three statements can bypass foreign-key and CHECK constraints until commit","Wrapping the three writes in one transaction makes them atomic: if any step fails, all are rolled back, so you never persist an order with no items or an unadjusted stock count. A transaction does not add automatic retries (b), does not parallelize statements (c), and does not disable constraints (d).",{"fields":215,"seniorities":391,"interview_shapes":392,"locales":397,"oauth":399,"question_count":402,"coach_enabled":403,"jd_match_enabled":403},[216,241,261,278,302,315,324,343,365,372,378,385],{"key":217,"name_tr":218,"name_en":218,"sort":132,"specializations":219},"backend","Backend",[220,223,226,229,232,235,238],{"key":221,"name":222,"field":217},"general","Genel",{"key":224,"name":225,"field":217},"go","Go",{"key":227,"name":228,"field":217},"python","Python",{"key":230,"name":231,"field":217},"java","Java",{"key":233,"name":234,"field":217},"csharp","C#\u002F.NET",{"key":236,"name":237,"field":217},"nodejs","Node.js",{"key":239,"name":240,"field":217},"php","PHP",{"key":242,"name_tr":243,"name_en":243,"sort":163,"specializations":244},"frontend","Frontend",[245,246,249,252,255,258],{"key":221,"name":222,"field":242},{"key":247,"name":248,"field":242},"javascript","JavaScript",{"key":250,"name":251,"field":242},"typescript","TypeScript",{"key":253,"name":254,"field":242},"react","React",{"key":256,"name":257,"field":242},"vue","Vue",{"key":259,"name":260,"field":242},"angular","Angular",{"key":262,"name_tr":263,"name_en":263,"sort":264,"specializations":265},"fullstack","Fullstack",3,[266,267,268,269,270,271,272,273,274,275,276,277],{"key":221,"name":222,"field":262},{"key":224,"name":225,"field":217},{"key":227,"name":228,"field":217},{"key":230,"name":231,"field":217},{"key":233,"name":234,"field":217},{"key":236,"name":237,"field":217},{"key":239,"name":240,"field":217},{"key":247,"name":248,"field":242},{"key":250,"name":251,"field":242},{"key":253,"name":254,"field":242},{"key":256,"name":257,"field":242},{"key":259,"name":260,"field":242},{"key":279,"name_tr":280,"name_en":280,"sort":281,"specializations":282},"devops-cloud","DevOps \u002F Cloud",4,[283,284,287,290,293,296,299],{"key":221,"name":222,"field":279},{"key":285,"name":286,"field":279},"aws","AWS",{"key":288,"name":289,"field":279},"gcp","GCP",{"key":291,"name":292,"field":279},"azure","Azure",{"key":294,"name":295,"field":279},"kubernetes","Kubernetes",{"key":297,"name":298,"field":279},"terraform","Terraform",{"key":300,"name":301,"field":279},"linux","Linux",{"key":303,"name_tr":304,"name_en":304,"sort":305,"specializations":306},"ai-engineer","AI Engineer",5,[307,308,309,312],{"key":221,"name":222,"field":303},{"key":227,"name":228,"field":303},{"key":310,"name":311,"field":303},"llm-rag","LLM\u002FRAG",{"key":313,"name":314,"field":303},"mlops","MLOps",{"key":5,"name_tr":316,"name_en":6,"sort":317,"specializations":318},"Veritabanı",6,[319,320,321,322,323],{"key":221,"name":222,"field":5},{"key":124,"name":125,"field":5},{"key":121,"name":122,"field":5},{"key":117,"name":118,"field":5},{"key":127,"name":128,"field":5},{"key":325,"name_tr":326,"name_en":327,"sort":328,"specializations":329},"mobile","Mobil","Mobile",7,[330,331,334,337,340],{"key":221,"name":222,"field":325},{"key":332,"name":333,"field":325},"ios-swift","iOS (Swift)",{"key":335,"name":336,"field":325},"android-kotlin","Android (Kotlin)",{"key":338,"name":339,"field":325},"flutter","Flutter",{"key":341,"name":342,"field":325},"react-native","React Native",{"key":344,"name_tr":345,"name_en":346,"sort":347,"specializations":348},"security","Güvenlik","Security",8,[349,350,353,356,359,362],{"key":221,"name":222,"field":344},{"key":351,"name":352,"field":344},"appsec","AppSec",{"key":354,"name":355,"field":344},"offensive-pentest","Offensive \u002F Pentest",{"key":357,"name":358,"field":344},"cloud-security","Cloud Security",{"key":360,"name":361,"field":344},"devsecops","DevSecOps",{"key":363,"name":364,"field":344},"blue-team-incident","Blue Team \u002F Incident",{"key":366,"name_tr":367,"name_en":368,"sort":369,"specializations":370},"qa-test-automation","QA \u002F Test Otomasyonu","QA \u002F Test Automation",9,[371],{"key":221,"name":222,"field":366},{"key":373,"name_tr":374,"name_en":374,"sort":375,"specializations":376},"data-engineer","Data Engineer",10,[377],{"key":221,"name":222,"field":373},{"key":379,"name_tr":380,"name_en":381,"sort":382,"specializations":383},"game-dev","Oyun Geliştirme","Game Development",11,[384],{"key":221,"name":222,"field":379},{"key":386,"name_tr":387,"name_en":387,"sort":388,"specializations":389},"ml-engineer","ML Engineer",12,[390],{"key":221,"name":222,"field":386},[14,15,16],{"junior":393,"mid":395,"senior":396},{"questions":394,"median_sec":3},20,{"questions":394,"median_sec":3},{"questions":394,"median_sec":3},[398,10],"tr",[400,401],"google","github",21750,true]