ANSI Standards – Database – Substring

Background Reviewing some SQL and wanted to point out a tiny dissimilarity between database platforms. Data Our test table is Oracle's SCOTT.EMP Here is what the data looks like :- Substring/Substr The HIREDATE is the only well formatted fixed length string. Its format is DD-MMM-YY. Query Oracle SQL Output Explanation Oracle relies on Substr to … Continue reading ANSI Standards – Database – Substring

Database – Buffer Pool – Clearing

Background During Database performance stressing, data is ingested into memory and written to disk. As one tries out different database table structures and Data Manipulation Languages ( DML ) queries, one often finds it useful to clean the slate in between.   Granularity Like any other operation one can target processing against the server, database, … Continue reading Database – Buffer Pool – Clearing

Oracle :- Numbers Table

Background Let us create and populate a numbers table. Code Outline Creating a numbers table is a bit more complicated. And, it's complexity is dependent on Version of Oracle. Steps Create Table Identity Column To me identity column is a bit easier that Sequence Run Statement N Times In Transact SQL, we use go In … Continue reading Oracle :- Numbers Table

Hibernate – Error Message – “Unknown entity”

Background Learning new tooling is not easy for me. Error Image Textual Trouble Shooting Metadata Entities Registered Outline Start a Session or use an existing one Get Session's Transaction handle Start a new transaction Get Session's metamodel Get Metamodel entity list Iterate Metamodel entity list Commit Transaction Code Similar Errors @OneToOne or @ManyToOne on [entity] … Continue reading Hibernate – Error Message – “Unknown entity”

Apache – jMeter – Preparation – Java JRE

Background Pardon the pun, but measuring out jMeter appropriateness for a task we have at hand. Error image   textual jmeter Not able to find Java executable or version. Please check your Java installation. errorlevel=2 Press any key to continue . . .   Troubleshooting Validation JRE Outline Let us see if we have JRE … Continue reading Apache – jMeter – Preparation – Java JRE

DBeaver – Database Connection Configuration – Oracle – Oracle JDBC Driver

Background Towards a couple of sample Oracle Database sample exercises that we have in mind wanted to make sure that our all purpose database client, DBeaver, is able to communicate with an Oracle Database.   Preparation Oracle Java Version Objective The version of JDBC Client that we need will be based on the version of … Continue reading DBeaver – Database Connection Configuration – Oracle – Oracle JDBC Driver

Oracle Database Client on Windows

Background In the last couple of posts we touched on installing Oracle XE to avail a small footprint Oracle DB Server. Later we used SQLPlus to validate connectivity and add a new 'regular' user.   Lineage “Oracle Database 11g Express Edition” – Installation on Windows Link Oracle – SQLPlus – Create new User Link Download … Continue reading Oracle Database Client on Windows