Beginning Amazon DynamoDB

What Is Amazon DynamoDB?Amazon DynamoDB is a fully managed NoSQL database service that provides fast and predictable performance with seamless scalability. NoSQL is a term used to describe nonrelational database systems that are highly available, scalable, and optimized for high performance. Instead of the relational model, NoSQL databases (like DynamoDB) use...

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MyBatis introduction

 MyBatis is a Java persistence framework that couples objects with stored procedures or SQL statements using an XML descriptor or annotations.MyBatis is free software that is distributed under the Apache License 2.0. MyBatis is a fork of iBATIS 3.0 and is maintained by a team that includes the original creators of iBATIS. MyBatis is a first class persistence framework with support for ...

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Oracle SQL căn bản P2

1> Execute a function that is defined in a package Question: How can I execute a function that is defined in a package using Oracle/PLSQL? Answer: To execute a function that is defined in a package, you'll have to prefix the function name with the package name. package_name.function_name (parameter1, parameter2, ... parameter_n) You can execute a function a few different wa...

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Beginning elasticsearch

1.Elasticsearch concepts wikipedia talks about elasticsearch: Elasticsearch is a search engine based on Lucene. It provides a distributed, multitenant-capable full-text searchengine with an HTTP web interface and schema-free JSON documents. Elasticsearch is developed in Java and is released as open source under the terms of the Apache...

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Database normalization Introduction

Definition from wikipedia Database normalization is the process of restructuring a relational database in accordance with a series of so-called normal forms in order to reduce data redundancyand improve data integrity. It was first proposed by Edgar F. Codd as an integral part of his relational model. Normalization entails organizing the columns (attributes)...

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LEFT JOIN vs. LEFT OUTER JOIN in SQL

As per the documentation: FROM (Transact-SQL): <join_type> ::= [ { INNER | { { LEFT | RIGHT | FULL } [ OUTER ] } } [ <join_hint> ] ] JOIN The keyword OUTER is marked as optional (enclosed in square brackets), and what this means in this case is that whether you specify it or not makes no difference. Note that while the other elements of the join clause is also marked as optional,...

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JPA Criteria API

Using the Criteria API to Create Queries The Criteria API is used to define queries for entities and their persistent state by creating query-defining objects. Criteria queries are written using Java programming language APIs, are typesafe, and are portable. Such queries work regardless of the underlying data store. The following topics are addressed here: Overview of the Criteria and Metamodel...

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JPA Select Statements and NamedQuery

Select Statements A select query has six clauses: SELECT, FROM, WHERE, GROUP BY, HAVING, and ORDER BY. The SELECT and FROM clauses are required, but the WHERE, GROUP BY, HAVING, and ORDER BY clauses are optional. Here is the high-level BNF syntax of a query language select query:      Note: some of the terms...

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Ordinary JPA Query API

Queries are represented in JPA 2 by two interfaces - the old Query interface, which was the only interface available for representing queries in JPA 1, and the new TypedQuery interface that was introduced in JPA 2. The TypedQuery interface extends the Query interface. In JPA 2 the Query interface should be used mainly when the query result type...

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JavaDB Connection pool

From Wikipedia, the free encyclopedia In software engineering, a connection pool is a cache of database connections maintained so that the connections can be reused when future requests to the database are required.[citation needed] Connection pools are used to enhance the performance of executing commands on a database. Opening and maintaining a database...

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