Database – Jun Kim

How to combine multiple rows into a single string in Oracle

October 4, 2023Jun Kim

This was the question in my mind that how to concatenate multiple rows into single column. We can do with built-in function called ‘listagg’.This is the example of the code

.NET, Clean Coding, Database

Update entity with Auto Mapper

March 11, 2022March 11, 2022Jun Kim

When we try to update the existing date with Entity Framework, you might to following steps. In above case, application will get following error. To resolve this error, this .AsNoTracking()…Continue readingUpdate entity with Auto Mapper

.NET, Database

Automapper Aftermap “method not found” exception

March 11, 2022March 11, 2022Jun Kim

When you tried to add AutoMapper to IOC container or ASP .NET Service, you may or not encounter following error. Mostly not. When I had this, I spent so much…Continue readingAutomapper Aftermap “method not found” exception

Database, Oracle

How to change NLS Setting

April 23, 2020April 23, 2020Jun Kim

Sometimes, Oracle SQL Developer display the date format as ‘DD-MM-YY’ although I changed the format on the preference. To change it manually on the session run following query. ALTER SESSION…Continue readingHow to change NLS Setting

Database, Oracle

Oracle / PLSQL: CREATE TABLE AS Statement

April 1, 2020October 14, 2020Jun Kim

The syntax for the CREATE TABLE AS statement that copies all of the columns in Oracle/PLSQL is: CREATE TABLE new_table AS (SELECT * FROM old_table); Example Let’s look at a…Continue readingOracle / PLSQL: CREATE TABLE AS Statement

.NET, Clean Coding, Oracle

Entity Framework 6 with Oracle Code First Design Configuration

March 10, 2020Jun Kim

Microsoft Entity Framework abstracts the relational, logical database schema and presents a conceptual schema to the .NET application. It provides object-relational mapping for .NET developers. Code First allows developers to…Continue readingEntity Framework 6 with Oracle Code First Design Configuration

Database, Oracle

For Loop

February 13, 2020Jun Kim

How to use for loop in Oracle FOR loop_counter IN [REVERSE] lowest_number..highest_number LOOP {…statements…} END LOOP; [REVERSE]: Optional. The loop counter will count in reverse. If REVERSE is specified, then…Continue readingFor Loop

.NET, Clean Coding, Database

Database Concurrency (Isolation Level)

January 3, 2020Jun Kim

This is the articles that I found related to Isolation Level. It’s helpful to handle database concurrency issue. Databases (and other transactional systems) attempt to ensure transaction isolation, meaning that,…Continue readingDatabase Concurrency (Isolation Level)

Database, Oracle

DBMS_OUTPUT not working (Doesn’t display anything)

December 31, 2019Jun Kim

From the Oracle SQL Developer, when you can’t see any output although you added DBMS_OUTPUT as following: BEGIN DBMS_OUTPUT.PUT_LINE(‘This should be displayed’); END; It doesn’t display anything as following: You…Continue readingDBMS_OUTPUT not working (Doesn’t display anything)

Database, Oracle

Merge Code Sample – Oracle

December 24, 2019Jun Kim

It’s Oracle Script. The Oracle MERGE statement selects data from one or more source tables and updates or inserts it into a target table. The MERGE statement allows you to specify a condition to determine whether to update data…Continue readingMerge Code Sample – Oracle

Category: Database