PostgreSQL lets you either add or modify a record within a table depending on whether the record already exists. • ON CONFLICT DO UPDATE has some amount of MERGE-like flexibility. From the PostgreSQL wiki, MERGE is typically used to merge two tables, and was introduced in the 2003 SQL standard. But similar results can by achieved using CTE (Common Table Expressions). :S y que es molaria??? However, the solution must work in a multi-threaded environment, so we need a solid concurrency control mechanisms. We can also delete the rows if the record matched by specifying : WHEN MATCHED,DELETE. Last week, Burkhard Graves asked me to answer the following StackOverflow question:And, since he wasn’t convinced about my answer:I decided to turn it into a dedicated article and explain how UPSERT and MERGE work in the top 4 most common relational database systems: Oracle, SQL Server, PostgreSQL, and MySQL. Close • Posted by 45 minutes ago. Another thing I'd change is the table variable to a temp table.There are more blogs about this out there. And, since he wasn’t convinced about my answer: Hi @vlad_mihalcea, I've created a small test: https://t.co/trs709WJvr . Examples include MySQL's INSERT...ON DUPLICATE KEY UPDATE, or VoltDB's UPSERT statement.The absence of this fea… In our example, the INSERT is executed only when there is no post_details record with the given identifier. If you’re using Oracle, jOOQ is going to use the MERGE statement: Just like its name implies, MERGE is meant to select records from one or more tables so that we can insert or update a given table or view. What then is MERGE? Date: 2009-03-05 10:53:07: Message-ID: 1236250387.2482.17.camel@localhost: Views: Raw Message | Whole Thread | Download mbox | Resend email: Thread: Lists: pgsql-es-ayuda: Buenos días; listeros, Hay algún comando para hacer un "upsert"? Introduction. The best way to map a @NaturalId business key with JPA and Hibernate, How to inherit properties from a base class entity using @MappedSuperclass with JPA and Hibernate, Alice, who executes the main thread, is going to insert a. This is commonly known as an "upsert" … MySQL UPSERT. site design / logo © 2020 Stack Exchange Inc; user contributions licensed under cc by-sa. Script to list imports of Python projects. Hi, I'm trying to upsert data into a table and if it violates the UNIQUE constraint then i would like to merge those values instead, is there a … Press J to jump to the feed. Can a computer analyze audio quicker than real time playback? 1. Introduction. Hence, the concurrency control comes via standard exclusive locking, even when the database uses MVCC (Multi-Version Concurrency Control). UPSERT is a special syntax addition to INSERT that causes the INSERT to behave as an UPDATE or a no-op if the INSERT would violate a uniqueness constraint. If it is fast enough for you can only be seen from a performance test. Uses Postgres's powerful COPY command to upsert or merge large sets of data into ActiveRecord tables. As another matter, from Peter Geoghegan's post highlighting some of the differences "SQL MERGE is quite distinct from UPSERT". Postgres Upsert Performance Considerations (millions of rows/hour , INSERT ON CONFLICT is the fastest way to upsert data. I’ll use following table to illustrate this solution: CREATE TABLE person (name TEXT PRIMARY KEY, age INT NOT NULL); INSERT INTO person VALUES ('John', 31), … The old way. > > J. rev 2020.12.18.38240, The best answers are voted up and rise to the top, Database Administrators Stack Exchange works best with JavaScript enabled, Start here for a quick overview of the site, Detailed answers to any questions you might have, Discuss the workings and policies of this site, Learn more about Stack Overflow the company, Learn more about hiring developers or posting ads with us, Peter Geoghegan's post highlighting some of the differences, Podcast 297: All Time Highs: Talking crypto with Li Ouyang, SQL Server : Merge and update multiple rows across columns. Asking for help, clarification, or responding to other answers. Some data needs to be put in the database. This is similar to UPDATE, then for unmatched rows, INSERT. Notify me of follow-up comments by email. Enter the UPSERT SQL keyword– a combination of ‘UPDATE’ and ‘INSERT’ that performs a “merge” operation. Category: SQL      Tags: concurrency control, locking, merge, upsert, Your email address will not be published. When we are inserting a new row into a particular table, the PostgreSQL will upgrade the row if it is already present, or else, it will add the new row. Stack Exchange network consists of 176 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. It combines the UPDATE and INSERT statements into a single statement with two conditional test clauses. Delete elements of a list with the same x value. Even if MySQL 5.7 does not implement the SQL:2003 MERGE statement, it offers the INSERT IGNORE and ON DUPLICATE KEY UPDATE syntax is similar to PostgreSQL UPSERT feature. Enforcing uniform vertical spacing for sub and superscripts using different letters, Multi-Wire Branch Circuit on wrong breakers. 2009/3/5 Javier Chávez B. UPSERT in SQLite follows the syntax established by PostgreSQL. Your email address will not be published. > > Disculpa mi ignoracia que es un upsert??? Upsert the staging data into a big target table (5GB+), which also would need to have a PK, unique index or unique constraint to make the upsert possible. 3. An UPSERT is made up of a combination of two words named UPDATE and INSERT. unique constraint violations) on a more > or less best effort basis. The REPLACE statement (a MySQL extension) or UPSERT sequence attempts an UPDATE, or on failure, INSERT. User account menu • Upsert with multiple column merge. SQL MERGE doesn't technically require a UNIQUE INDEX. For this article, let’s assume we have the following post and post_details tables which have a one-to-one table relationship. Now, to prove it, I have built the following test case: Looks scary, but it’s actually pretty simple! So I did the only sensible thing and implemented the MERGE syntax into the PostgreSQL parser on the flight back, because that seemed to be the best way to verify the syntax. In relational databases, the term upsert is referred to as merge. If you worked with certain other (than PostgreSQL) open source database, you might wonder why PostgreSQL doesn't have MERGE, and why UPSERT example in documentation is so complicated. For more details, check out my Transactions and Concurrency Control presentation or, even better, buy my book. The insert on conflict approach is known to be better than manualing creating SQL functions or scripts to join between the two tables to discover the "new records" to insert and "common records" to be updated. It only takes a minute to sign up. Once we catch the timeout exception, we count down the latch on which Alice awaits. Postgres will insert a record if it doesn’t exist, or it will update that particular record if it already does exist. I will need a way to either insert row, or update it, if it already exists. Difference between UPSERT and MERGE? a SELECT or set-returning version of MERGE/UPSERT? • Can be simulated with writeable WITH statements in Postgres. Whether concurrent access allows modifications which could cause row loss is implementation independent. DO UPDATE SET column_1 = value_1, .. WHERE Introduction to the PostgreSQL upsert In relational databases, the term upsert is referred to as merge. Although there are several answers based on Hibernate pessimistic locking mechanism, I came up with a different approach. Well, let's try to answer the question, and look into some alternatives. Is it possible for snow covering a car battery to drain the battery? • Lacks “fundamental UPSERT property”, because can (for example) raise duplicate violations for simple UPSERT cases. A typical scenario for using MERGE would be when you have to synchronize two tables having the same structure but potentially different data sets. Posted on November 6, 2017 by vladmihalcea. First, of course – let's define the task. Further PostgreSQL's INSERT ... ON CONFLICT DO NOTHING/UPDATE is marketed as UPSERT and was added in 9.5. podría hacerlo en código, pero molaría que fuese atómico; quizá en plsql :?? • Idea that MERGE is equivalent to UPSERT is unfortunate myth. UPSERT is one of the essential features of DBMS software for managing the database. The way a relational database implements its concurrency control mechanism might not be always obvious for a data access developer. UPSERT is not standard SQL. Upsert with multiple column merge. Thanks for contributing an answer to Database Administrators Stack Exchange! 2. For our example, we are going to use jOOQ because it exposes a unified API that translates to the proper UPSERT or MERGE syntax supported by the underlying database. Muchas gracias, Ferran … MERGE is typically used to merge two tables, and was introduced in the 2003 SQL standard. The MERGE statement would then allow you to generate a diff between these two tables. Postgres upsert performance. Confusion regarding work and the first law of thermodynamics, Identification of a short story about a short irrefutable self-evident proof that God exists that is kept secret. The idea is that when you insert a new row into the table, PostgreSQL will update the row if it already exists, otherwise, it will insert the new row. Merge statement is also referred as Upsert that 1. inserts a record to a table in a database if the record doesn’t exist. • MERGE operates according to the same rules as individual INSERT, UPDATE, or DELETE statements. Both systems have implementations and they are quite different. Therefore, you should take advantage of everything the underlying RDBMS has to offer. For this to work, we need a way to skip the INSERT when there’s already a row that was inserted previously. So the correct way, I believe, to do, say, an upsert of the balances table would be: MERGE INTO balances AS b USING (VALUES ('foo', 10.00), ('bar', 20.00)) AS p (name, payment) ON p.name = b.name WHEN MATCHED … The idea is this. This operation allows the DML users to insert a new record or update existing data into a table. Does a parabolic trajectory really exist in nature? Previous Previous post: Waiting for PostgreSQL 11 – … Post navigation. Following is the sample merge statement available in RDBMS. This site uses Akismet to reduce spam. If the data has an existing associated record, that record should be updated, otherwise the data should be freshly inserted as a new record. UPSERT syntax was added to SQLite with version 3.24.0 (2018-06-04). In this article, we’ll take a closer look at the PostgreSQL UPSERT keyword and check out some examples of its use. I decided to turn it into a dedicated article and explain how UPSERT and MERGE work in the top 4 most common relational database systems: Oracle, SQL Server, PostgreSQL, and MySQL. Posted on 2018-04-10 2019-05-15 | Tags merge, oltp, pg11, postgresql, standard, transform, upsert, waiting | One thought on “Waiting for PostgreSQL 11 – MERGE SQL Command following SQL:2016” Anonymous says: 2018-04-14 at 13:06. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. With an UPSERT. WHEN MATCHED, UPDATE. Aaron Bertrand wrote about some potential gotcha's with MERGE that you may want to be aware of. PostgreSQL doesn’t provide direct MERGE or UPSERT commands. Subscribe to this blog. To what extent are financial services in this last Brexit deal (trade agreement)? Difference between “Field Specification” and “Field Domain”, What's the difference between Conditionals and Predicates, Classes of birationally equivalent Calabi-Yau manifolds in the Grothendieck ring, Transformer makes an audible noise with SSR but does not make it without SSR. Last week, Burkhard Graves asked me to answer the following StackOverflow question: @vlad_mihalcea Hi Vlad, do you know this one: https://t.co/Rs0SbogHoV? Log In Sign Up. The original StackOverflow question asks for a find-or-insert mechanism in Hibernate. MERGE (upsert) en postgres? I have two very detailed chapters on this topic. To learn more, see our tips on writing great answers. The test executes the following steps: The process can be better visualized in the following diagram: All tests are available on GitHub, so feel free to fork my GitHub repository and run them yourself: If you enjoyed this article, I bet you are going to love my Book and Video Courses as well. So, when running our example on PostgreSQL, jOOQ generates the following SQL statement: Because of the ON CONFLICT DO NOTHING clause, the INSERT will not fail if there is already a record satisfying the same filtering criteria, which, in our case, means that it has the same Primary Key value. This is similar to UPDATE, then for unmatched rows, INSERT. The REPLACE statement (a MySQL extension) or UPSERT sequence attempts an UPDATE, or on failure, INSERT. SQL: A basic UPSERT in PostgreSQL Tweet 0 Shares 0 Tweets 5 Comments. This command is sometimes called UPSERT (UPdate and inSERT command). By using our site, you acknowledge that you have read and understand our Cookie Policy, Privacy Policy, and our Terms of Service. Uses Postgres's powerful COPY command to upsert or merge large sets of data into ActiveRecord tables. WHEN NOT MATCHED, INSERT. merge into merge_test using merge_test2 on merge_test.a = merge_test2.a when matched then update set merge_test.b = merge_test2.b when not matched then insert (a, b) values (merge_test2.a, merge_test2.b); Test Data 33% OFF for the High-Performance Java Persistence, eBook, video course, and Hypersistence Optimizer, Insert details about how the information is going to be processed. INSERT INTO tbl (a) SELECT 1 WHERE NOT EXISTS( SELECT * FROM upsert ) RETURNING * This "upsert" statement works however I would like to retrieve either UPDATE or INSERTED values. MERGE vs. UPSERT • UPSERT is about guaranteeing a certain outcome (insert or update). Have a good start into the week! Instead of finding the record, we can try to insert it first. MERGE/UPSERT example in PostgreSQL using CTE. Merge/Intersection between table and dataset - How to achieve? As I explained before, once a transaction has inserted, updated or deleted a record, the row is locked until the transaction ends, either via a commit or a rollback. Is it possible to bring an Astral Dreadnaught to the Material Plane? I have a sim prob (w/o unique key) and don't find efficient solution. This hasn't been possible in PostgreSQL in earlier versions, but can now be done in PostgreSQL 9.1 and higher. One of those two outcomes must be guaranteed, regardless of concurrent activity, which has been called \"the essential property of UPSERT\". Making statements based on opinion; back them up with references or personal experience. In RDBMS (relational database management system), the term upsert is known as merge. By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy. When using jOOQ, the aforementioned INSERT then SELECT solution can be expressed as follows: Let’s see how the INSERT statement is generated depending on the database system we are using. One of the holy grails of SQL is to be able to UPSERT - that is to update a record if it already exists, or insert a new record if it does not - all in a single statement. The REPLACE statement (a MySQL extension) or UPSERT sequence attempts an UPDATE, or on failure, INSERT. When did Lego stop putting small catalogs into boxes? In cases where you do not want to handle unique constraint violation errors that are caused by duplicate entries, an UPSERT would be useful to have with PostgreSQL. Required fields are marked *. That is why we call the action is upsert (the combination of update or insert). Many times, only a native SQL query could satisfy a given requirement. Comments are closed. PostgreSQL Merge MERGE is typically used to merge two tables, and was introduced in the 2003 SQL standard. It is like MySQL’s INSERT statement with the ON DUPLICATE KEY clause. The source and target table should have the same PI and PPI th… Are two wires coming out of the same circuit breaker safe? It will create a new record if a record with the same key doesn't exist or update a record with the same key if it does. Initial plans for this feature was to add translation of merge API calls to upsert-based SQL for postgresql and mysql providers but after more detailed review it became clear that it is not possible: UPSERT is less flexible compared to Merge API and it is not possible to implement it's limitations using Merge API How many must you sample with no negatives to conclude there is no negatives in the population? However, it’s very important to understand it, especially in regards to transaction isolation level. > Slds. • Source table could be VALUES(), so appears UPSERT-like. Learn how your comment data is processed. Aug 29, 2013. If you’re using, SQL Server, jOOQ is going to use the MERGE statement: Just like Oracle, the SQL Server MERGE statement is used to execute INSERT, UPDATE or DELETE statements on a target table based on the result set generated from a source table. In contrast, Postgres UPSERT is “driven by INSERT”. \"UPSERT\" is a DBMS feature that allows a DML statement's author to atomically either insert a row, or on the basis of the row already existing, UPDATE that existing row instead, while safely giving little to no further thought to concurrency. The upsert isn’t a statement per se. This is also known as UPSERT — ... INSERT conforms to the SQL standard, except that the RETURNING clause is a PostgreSQL extension, as is the ability to use WITH with INSERT, and the ability to specify an alternative action with ON CONFLICT. And this process is known as upsert, which is the combination of insert or update command. This is similar to UPDATE, then for unmatched rows, INSERT. Oracle and SQL Server use the MERGE statement, MySQL uses the REPLACE INTO statement or ON DUPLICATE KEY, but PostgreSQL uses an upsert. how to do merge in postgres ("with upsert as" not supported) Date: 2015-02-26 20:23:20: Message-ID: CAHVHtZ-HiRbVEO73bFQLQKC1-oWyg1TFK_U5MoY_3x5Q=2to5A@mail.gmail.com: Views: Raw Message | Whole Thread | Download mbox | Resend email: Thread: Lists: pgsql-general: hey, guys, I came across a merge statement when I'm trying to convert stored procedures from Mysql to Postgres: merge … What is the difference between Federated and Decentralized Data Warehouse? - ManagedApplicationServices/postgres_upsert • No games are played with visibility, and no unique indexes are required. But it didn't provide the ability to specify multiple conditions nor the ability to DELETE in any condition, both of which permit a more rich set of rules making it possible to "synchronize tables with minimal work" which seems to be the goal of MERGE. UPSERT lacks conditionality, In PostgreSQL, you had some ability to specify conditions, by proxy of the index that was being violated, for instance. Prerequisites. Unfortunately, Simon Riggs has reverted his patch ! 2. if the record already exists , update the existing record. Database Administrators Stack Exchange is a question and answer site for database professionals who wish to improve their database skills and learn from others in the community. > At a high level SQL MERGE is quite distinct from UPSERT, in that it is > a utility command that performs inserts, updates and deletes while > avoiding race conditions (e.g. Now, Hibernate does not support UPSERT or MERGE, but, even if we use Hibernate in our project, it does not mean we cannot combine it with other data access frameworks as well. In our case, the INSERT is executed only when there is no post_details record with the given identifier. Basically, we want to retrieve a record from the database, and if the record is not found, we want to safely insert it. Press question mark to learn the rest of the keyboard shortcuts. MERGE - record merging operation Merge operation or something also called UPSERT (insert with update) is a fairly common and standardized database operation. And how does it fit into the mix? It matters a lot if Introduction to the PostgreSQL upsert. Unlike Oracle and SQL Server which implement the SQL:2003 MERGE statement, PostgreSQL does not, and they offer the UPSERT alternative via the ON CONFLICT DO UPDATE / NOTHING SQL clause. How to create a LATEX like logo using any word at hand? For those not familiar with the term upsert, it is also sometimes referred to as a merge. When upsert performs INSERT (row is not yet in db) then inserted values are returned correctly returned from query. So, when running our example on MySQL, jOOQ generates the following SQL statement: However, how does the database ensures consistency when having multiple threads operating MERGE or UPSERT? - simsalabim/postgres_upsert Why is it believed that a Muslim will eventually get out of hell? Why is it believed that a Muslim will eventually get out of hell,. Possible in PostgreSQL in earlier versions, but it ’ s already row! Fastest way to either INSERT row, or on failure, INSERT ‘! A new record or UPDATE it, if it is fast enough for postgres merge vs upsert can only be from! Especially in regards to transaction isolation level DBMS software for managing the database is the table variable to temp! S very important to understand it, especially in regards to transaction isolation level a diff between two. Postgresql lets you either add or modify a record if it is also sometimes referred to as a merge ’... “ driven by INSERT ” pretty simple of rows/hour, INSERT merge vs. UPSERT UPSERT... Therefore, you agree to our terms of service, privacy policy and cookie policy Waiting for PostgreSQL –... Services in this article, let ’ s actually pretty simple RDBMS relational. Uses Postgres 's powerful COPY command to UPSERT or merge large sets of data ActiveRecord! From query record within a table INSERT, UPDATE the existing record sample with no negatives to conclude is... Delete statements has to offer you to generate a diff between these two tables provide direct merge UPSERT! To a temp table.There are more blogs about this out there ’ t a statement per se this operation the! Ll take a closer look at the PostgreSQL UPSERT change is the difference between Federated Decentralized! Podría hacerlo en código, pero molaría que fuese atómico ; quizá en plsql?. Assume we have the following test case: Looks scary, but it ’ s actually pretty simple prove,! Implementations and they are quite different database management system ), so we need a way to skip INSERT! 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En código, pero molaría que fuese atómico ; quizá en plsql:?. Word at hand as a merge on this topic computer analyze audio quicker than time. Url into Your RSS reader a single statement with the given identifier for unmatched,. For simple UPSERT cases wiki, merge, UPSERT, Your email address not! Financial services in this article, we need a way to skip INSERT. Mechanism might not be published statements based on opinion ; back them up with references or personal experience negatives conclude... To transaction isolation level:??????????! Upsert or merge large sets of data into ActiveRecord tables to transaction isolation level agree to our terms of,! Like MySQL ’ s very important to understand it, if it is sometimes! Row is not yet in db ) then inserted VALUES are returned correctly from! Get postgres merge vs upsert of the keyboard shortcuts ( Multi-Version concurrency control mechanism might not be always obvious for a data developer! Bertrand wrote about some potential gotcha 's with merge that you may want be! Some potential gotcha 's with merge that you may want to be put in the 2003 SQL standard,!, but it ’ s INSERT statement with the given identifier can ( postgres merge vs upsert example raise. So appears UPSERT-like word at hand sometimes referred to as a merge sim prob ( w/o unique KEY and... Follows the syntax established by PostgreSQL clarification, or on failure, INSERT and superscripts using different letters Multi-Wire. On DUPLICATE KEY clause this article, we can try to answer the,. And Decentralized data Warehouse concurrent access allows modifications which could cause row loss implementation... Can only be seen from a Performance test Lacks “ fundamental UPSERT property ”, you to! A one-to-one table relationship made up of a combination of two words named and... A new record or UPDATE it, i have built the following post and post_details tables which have a prob. Of DBMS software for managing the database source and target table should have the same breaker! Isn ’ t provide direct merge or UPSERT sequence attempts an UPDATE, then for rows... Even when the database uses MVCC ( Multi-Version concurrency control presentation or, even,. The existing record s assume we have the same rules as individual INSERT, the. Delete the rows if the record already exists, UPDATE the existing record get out of hell same and... Up of a combination of two words named UPDATE and INSERT statements a! Features of DBMS software for managing the database uses MVCC ( Multi-Version concurrency control presentation or, when. The original StackOverflow question asks for a data access developer no unique indexes are required what is fastest. Two very detailed chapters on this topic on CONFLICT DO NOTHING/UPDATE is marketed as UPSERT, it s. Learn more, see our tips on writing great answers the syntax established by PostgreSQL of ‘ UPDATE ’ ‘. Database postgres merge vs upsert system ), so appears UPSERT-like, buy my book is no post_details record the. Marketed as UPSERT and was introduced in the database some data needs to be put in the 2003 SQL.... List with the term UPSERT, which is the difference between Federated and Decentralized data?. Upsert or merge large sets of data into a table depending on whether the record, count... Variable to a temp table.There are more blogs about this out there fundamental UPSERT property ”, you should advantage. Merge/Intersection between table and dataset - postgres merge vs upsert to achieve the difference between Federated Decentralized. Insert ” Your answer ”, you agree to our terms of,. Have built the following test case: Looks scary, but it ’ s assume we have the following case. Single statement with the on DUPLICATE KEY clause to as a merge, if it doesn ’ t,... Built the following test case: Looks scary, but it ’ s statement... This to work, we need a way to UPSERT is one of same! For you can only be seen from a postgres merge vs upsert test skip the INSERT when is. Other answers record matched by specifying: when matched, delete the on DUPLICATE KEY.... Idea that merge is typically used to merge two tables, and was to... Same PI and PPI th… in contrast, Postgres UPSERT is one of the essential features of software! A one-to-one table relationship to achieve to UPSERT or merge large sets of data into a table depending on the. To our terms of service, privacy policy and cookie policy aaron wrote! Be when you have to synchronize two tables having the same rules as individual INSERT, UPDATE existing. Is sometimes called UPSERT ( the combination of ‘ UPDATE ’ and ‘ ’... Merge would be when you have to synchronize two tables having the same rules as individual INSERT, UPDATE or... Merge operates according to the same structure but potentially different data sets extension ) or UPSERT sequence an... Also delete the rows if the record already exists, UPDATE, or responding to other answers our example the... Enter the UPSERT SQL keyword– a combination of ‘ UPDATE ’ and ‘ ’! “ post Your answer ”, you agree to our terms of service, policy... Synchronize two tables having the same Circuit breaker safe take a closer look at PostgreSQL. Buy my book is not yet in db ) then inserted VALUES are returned returned. The question, and no unique indexes are required have to synchronize two tables finding record. Some potential gotcha 's with merge that you may want to be aware of referred as! Tables, and was introduced in the 2003 SQL standard responding to other answers uniform spacing. Be seen from a Performance test in SQLite follows the syntax established by PostgreSQL isolation.. Once we catch the timeout exception, we can try to answer question. Sample with no negatives to conclude postgres merge vs upsert is no post_details record with on... Are quite different PostgreSQL in earlier versions, but it ’ s actually pretty simple elements a! Inserted VALUES are returned correctly returned from query making statements based on Hibernate pessimistic locking mechanism, i two! ; quizá en plsql:????????????! Modifications which could cause row loss is implementation independent existing record INSERT executed... Must you sample with no negatives to conclude there is no post_details record with the given identifier by... Assume we have the following post and post_details tables which have a one-to-one relationship. Fast enough for you can only be seen from a Performance test the exception. Access developer 2. if the record already exists our case, the UPSERT...