Jessica Qiu

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Top Stories by Jessica Qiu

Recently, we skillfully handled an industry project to import a great amount of data from file to Oracle in comparatively short time. At the beginning, we tried to import the data with the sqlldr of Oracle, only to find it is surprisingly time-consuming to load a great amount of data: Too slow if 2.5 hours have to be spent to import a table containing 80 million records. Later, by adopting the parallel import of sqlldr, the time is shortened to 0.8 hour. Here are the full details: Train of thoughts Split the data file to import into 10 shares. Then, with the multi-task parallelism, execute the sqlldr command for the corresponding shares. Needless to say, prepare the control files of the same amount. Then, multiple clients will start to import data to database all at the same time. Please note these two things: 1. The way to generate multiple sqlldr commands and corr... (more)

EsProc Enables Oracle JDBC to Speed Up Retrieve Process

Recently, a performance issue occurs in a big detail report, where the original data volume in the two data tables as it involved has exceeded 3 million rows; the data volume that the report can retrieve after filtering remains at round 2 million rows. As we expected before, by using paged retrieve method, this report would present a much higher performance. However, for the fact that the user also needs to export the data from the report, the only option is that the data retrieve can be achieved from Oracle at a time. As the JDBC of Oracle runs quite slowly, it takes least 6-7 ... (more)

Which Tool Will You Choose for Java: Hibernate, esProc, SQL, iBATIS or R?

The data computation layer in between the data persistent layer and the application layer is responsible for computing the data from data persistence layer, and returning the result to the application layer. The data computation layer of Java aims to reduce the coupling between these two layers and shift the computational workload from them. The typical computation layer is characterized with below features: Ability to compute on the data from arbitrary data persistence layers, not only databases, but also the non-database Excel, Txt, or XML files. Of all these computations, the... (more)

The Truth About Efficient Data Processes in Java Development

In Java development, the typical data computation problems are characterized with: Long computation procedure requiring a great deal of debugging Data may from database, or Excel/Txt Data may from multiple databases, instead of just one. Some computation goals are complex, such as relative position computation, and set-related computation Just suppose a sales department needs to make statistics on the top 3 outstanding salesmen ranking by their monthly sales in every month from Jan to the previous month, based on the order data. Java alone is difficult to handle such computations... (more)

Solving a JOIN Computation by SQL and esProc

Based on the generic data type, esProc provides the sequence and the Table Sequence for implementing the complete set-lizing and the much more convenient relational queries.   The relation between the department and the employee is one-to-many and that between the employee and the SSN (Social Security Number) is one-to-one. Everything is related to everything else in the world. The relational query is the access to relational dataset with the mathematical linguistics. Thanks to the associated query, the relational database (RDBMS) is extensively adopted. I Case and Comparison... (more)