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Category: Database

Oracle to Kafka made easy.

Oracle to Kafka made easy.

Source: http://oebsnotes.blogspot.com Sometimes we need to expose data from Oracle database to external systems/services.  In our experience, it ends ups with kind of interim tables or even interim databases or REST service solutions, the downsides of such approaches are well known. These days one of the best solution to communicate services is message broker, namely Apache Kafka.  This time we would like to send data from Oracle database to Kafka, after some googling we come up with – GoldenGate, WebLogic,…

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Installing oracle 11.2.0.4 under Docker

Installing oracle 11.2.0.4 under Docker

1. Upload the oracle installation package to the host and extract it (for example, under the directory of / data) [root@localhost data]# ll total 2487256 drwxr-xr-x. 7 440 200 4096 Aug 27 2013 database drwx——. 2 root root 16384 Aug 30 23:23 lost+found -rw-r–r–. 1 root root 1395582860 Aug 30 23:59 p13390677_112040_Linux-x86-64_1of7.zip -rw-r–r–. 1 root root 1151304589 Aug 30 23:59 p13390677_112040_Linux-x86-64_2of7.zip 2. Start with the image of Docker official website and mount / data to / install docker run -it –privileged…

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Oracle for Absolute Beginners: Date, Timestamp and Interval

Oracle for Absolute Beginners: Date, Timestamp and Interval

Source: https://www.red-gate.com/simple-talk/sql/oracle/oracle-for-absolute-beginners-date-timestamp-and-interval/ All databases stand on a tripod of datatypes: strings, numbers and dates. And though they might dress them in fancy clothing – varchar2, clob, float, integer – strings are really just strings, and numbers are really just numbers. But dates — dates are interesting. In this article I’ll talk to you about dates, about time, and about how both are All databases stand on a tripod of datatypes: strings, numbers and dates. And though they might dress them…

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Data consistency in Rails: Understanding the different between transaction and locking

Data consistency in Rails: Understanding the different between transaction and locking

Source Tất cả bắt nguồn từ bài post này của bên Grokking VietNam. Đại ý của bài viết như sau: Một ứng dụng chuyển tiền của ngân hàng có một đoạn code như dưới đây:

Ứng dụng chạy một thời gian thì có bug là tài khoản của một vài người dùng bị âm tiền. Vấn đề ở đây là gì và cách giải quyết. Mới đầu khi đọc bài viết tôi cũng thấy hơi khó hiểu khi đoạn code trên về…

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CONNECT BY basics

CONNECT BY basics

Source It builds a hierarchical query. There are 2 components to is: “start with” — this identifies all LEVEL=1 nodes in the tree “connect by” — describes how to walk from the parent nodes above to their children and their childrens children. Easiest to use an example on emp. If we start with “where mgr is NULL”, we generate the set of employees that have no mgr (they are the top of the tree). If we CONNECT BY PRIOR EMPNO…

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Bulk Processing with BULK COLLECT and FORALL

Bulk Processing with BULK COLLECT and FORALL

Source: https://blogs.oracle.com/oraclemagazine/bulk-processing-with-bulk-collect-and-forall In the previous article in this series, I introduced readers to PL/SQL collections. These data structures come in very handy when implementing algorithms that manipulate lists of program data, but they are also key elements in some of the powerful performance optimization features in PL/SQL. In this article, I will cover the two most important of these features: BULK COLLECT and FORALL. BULK COLLECT: SELECT statements that retrieve multiple rows with a single fetch, improving the speed of data…

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Binary Index Tree trong CSDL

Binary Index Tree trong CSDL

1 bài viết rất hay về tối ưu của tác giả Linh Trần Tuấn. Thích hợp cho giải pháp ERP bán lẻ: Link gốc: https://kipalog.com/posts/Binary-Index-Tree-trong-Co-so-du-lieu   Một trong những điểm thú vị nhất khi phát triển các hệ thống Business là lập báo cáo doanh thu. Mình đã từng maintain hệ thống cảnh báo sớm của Cục quản lý cạnh tranh, hệ thống do đối tác nào đó viết không phải mình. Trong bài viết này mình sẽ lấy hệ thống…

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