Typeorm repository transaction

Typeorm repository transaction


  • NestJS TypeORM Transaction Using QueryRunner
  • Per-Request Database Transactions with NestJS and TypeORM
  • How to perform a NestJS TypeORM Transaction using QueryRunner?
  • typescript – Nestjs Repository Pattern with Typeorm Transactions
  • TypeORM transactions not working as expected
  • NestJS TypeORM Transaction Using QueryRunner

    This is also the recommended way to handle transactions in NestJS. The need for transaction management Transactions are one of the most important concepts when dealing with databases. Basically, a transaction is a work unit. We should treat it as a whole. Either it happens completely or it does not happen.

    For example, you might consider transferring money from one account to another. The transfer fails if even one of the steps fails. Therefore, we should deal with such operations in the form of transactions.

    ACID property of the transactions A transaction must have the following properties. They are commonly known as ACID properties. Atomicity — This means that the operations of a transaction are a single entity that succeeds or fails. Consistency — A valid transaction brings the database from one valid state to another.

    Isolation — Transactions should be isolated. In other words, transactions can occur in parallel. Basically, valid transactions do not cause an inconsistent state. In addition, the intermediate transaction state should be invisible to other transactions. Durability Changes made to a transaction must be permanent.

    In other words, the changes should survive even a system failure. We will inject this class into ours Library service example. See the code below: library. The following import declaration will be required.

    It basically points to a pool of connections. To refer to a single database collection, we use QueryRunner grade. Basically all cases of QueryRunner is a connection. Then we store all the books in this case 2 books as part of the same transaction. If something goes wrong, we roll everything back. Otherwise, we commit the transaction and release the connection. You can find the code for the same on Github. If you have comments or questions about the post, feel free to write in the comments section below.

    Per-Request Database Transactions with NestJS and TypeORM

    Conclusion 1 — The Need of Transaction Management Transactions are one of the most important concepts while dealing with databases. Basically, a transaction is a unit of work. We should treat it as a whole. Either it happens completely or it does not happen. For example, you can think of transferring money from one account to another. The transfer fails if even one of the steps fail.

    Hence, we should handle such operations in the form of transactions. They are commonly known as ACID properties. Atomicity — This means that the operations in a transaction are a single unit that succeed or fail. Consistency — A valid transaction brings the database from one valid state to another. Isolation — Transactions should be isolated. In other words, transactions can occur concurrently. Also, the intermediate state of transaction should be invisible to other transactions.

    Durability — Changes made by a transaction should be durable. In other words, the changes should survive even a system failure.

    We will inject this class into our LibraryService example. The below import statement will be needed. It basically points to a pool of connections. To refer to a single database collection, we use the QueryRunner class. Basically, every instance of the QueryRunner is a connection. Then, we save all the books in this case 2 books as part of the same transaction. If something goes wrong, we rollback everything.

    Else, we commit the transaction and release the connection. You can find the code for the same on Github. If you have any comments or queries about the post, please feel free to write in the comments section below.

    How to perform a NestJS TypeORM Transaction using QueryRunner?

    Basically, a transaction is a unit of work. We should treat it as a whole. Either it happens completely or it does not happen.

    For example, you can think of transferring money from one account to another. The transfer fails if even one of the steps fail. Hence, we should handle such operations in the form of transactions.

    typescript – Nestjs Repository Pattern with Typeorm Transactions

    They are commonly known as ACID properties. Atomicity — This means that the operations in a transaction are a single unit that succeed or fail. We must treat it as a whole. For example, you might consider transferring money from one account to another. Migration fails if even one step fails.

    TypeORM transactions not working as expected

    Therefore, we must handle such an operation in the form of a transaction. ACID property of transactions A transaction must have the following characteristics.

    They are commonly known as ACID properties. Atomic — This means that the transactions in the transaction are the only unit that succeeds or fails. Separation — Transactions should be isolated. Consistency — A valid transaction brings the database from one valid state to another. Isolation — Transactions should be isolated. In other words, transactions can occur in parallel.

    Basically, valid transactions do not cause an inconsistent state. In addition, the intermediate transaction state should be invisible to other transactions. Durability Changes made to a transaction must be permanent. In other words, the changes should survive even a system failure. We will inject this class into ours Library service example. See the code below: library.


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