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Update Records in the databaseλ︎

Several options were explored when designing database query functions. Using next.jdbc.sql functions provides a Clojure data structures approach, where as next.jdbc/execute! uses specific SQL statement code.

Take the SQL approach if generating SQL statements directly.

Take the Clojure approach if to generate SQL statements from Clojure data structures.

Generic update record functionλ︎

Use the generic create function from the database schema design section

(defn update-record
  "Insert a single record into the database using a managed connection.
  - table - name of database table to be affected
  - record-data - Clojure data representing a new record
  - db-spec - database specification to establish a connection
  - where-clause - column and value to identify a record to update"
  [db-spec table record-data where-clause]
  (with-open [connection (jdbc/get-connection db-spec)]
    (jdbc-sql/update! connection table record-data where-clause)))

Update an existing account_holder recordλ︎

Call the update-record function with the development database specification, the account holder table name and a Clojure hash-map of the record data.

Each key in the map represents a column name and the value associated with the key is the value to be inserted in the record for its column.

  (update-record db-specification-dev
                 {:EMAIL_ADDRESS ""}
                 {:account_holder_id "f6d6c3ba-c5cc-49de-8c85-21904f8c5b4d"})

If the update is successful then :update-count 1 value is returned

  ;; => #:next.jdbc{:update-count 1}

Update an existing account recordλ︎

Update an existing record in the public.accounts table, providing new values for current_balance and last_updated columns.

(update-record db-specification-dev
               {:current_balance   242
                :last_updated      "2020-09-12"}
               {:account_number "1234567890"})

Update an existing transaction recordλ︎

Update an existing record in the public.transaction_history table.

(update-record db-specification-dev
               {:transaction_reference "Salary bonus"
                :transaction_date      "2020-09-12"}
               {:transaction_id  "8ac89cfc-6874-4ebe-9ee4-59b8c5e971ff"})

Generating example data from Clojure Spec

Clojure Spec: generate mock database data