Digital currency hive download app
1、 Different definitions:
1. virtual currency:
virtual currency refers to non real currency
digital currency:digital currency is an alternative currency in the form of electronic currency. Both digital gold coin and cryptocurrency belong to digiccy
3. Cryptocurrency:
cryptocurrency is a kind of transaction medium that uses cryptography principles to ensure transaction security and control the creation of transaction units
4. Token (token):
a kind of article whose shape and size are similar to currency, but the scope of use is limited and has no currency effect, and its token is the homonym of token in English
Second, the characteristics are different:1; It can also be said that virtual currency is personalized currency. In another way, it can also be called information currency
2. Digital currency:
is an unregulated and digital currency, which is usually issued and managed by developers and accepted and used by members of specific virtual communities
Cryptocurrency:cryptocurrency is based on the decentralized consensus mechanism, which is opposite to the banking and financial system relying on the centralized regulatory system
4. Token (token):
usually needs to be exchanged for money, used in shops, playgrounds, mass transportation and other places, as a voucher to use services and exchange goods
extended data
at present, digital currency is more like an investment proct, because it lacks a strong guarantee agency to maintain its price stability, and its role as a value measure has not yet appeared, so it can not be used as a means of payment. As an investment proct, digital currency cannot develop without trading platform, operating company and investment company
digital currency is a double-edged sword. On the one hand, the blockchain technology it relies on has been decentralized and can be used in other fields except digital currency, which is one of the reasons why bitcoin is popular; On the other hand, if digital currency is widely used by the public as a kind of currency, it will have a huge impact on the effectiveness of monetary policy, financial infrastructure, financial market and financial stability
1. The first step is to log on to the Com2us official website. Then we need to click "login" → "free registration member" in the upper right corner
1. To use hive, you need to start Hadoop first, because the use of hive depends on Hadoop's HDFS file system and maprec calculation. The figure below is to start Hadoop, as shown in the figure below
hive provides jdbc driver, which enables us to connect hive and perform some SQL query operations like relational database. First, we need to these drivers to the report project, then establish the connection, and finally query the data through the connection
jar package to fr project
hadoop-common.jar in Hadoop to report project appName / WEB-INF / lib
hive-exec.jar, hive-jdbc.jar, hive-metadata.jar, hive-service.jar, libfb303.jar, log4j.jar, slf4j api.jar, slf4j-log4j12.jar in hive to report project appName / WEB-INF / lib
configure data connection
start designer, open server & gt; Define data connection and create new JDBC connection.
Apache hive is one of the first software to introce SQL query function into Hadoop ecosystem. Among many other SQL on Hadoop procts are bigsql, drill, hadapt, impala and presto. In addition, Apache pig has become an alternative language to hiveql for Hadoop database< br/>
set Hadoop_ HOME
$ HADOOP_ Home = / path / to / some / Hadoop sqoop import -- arguments...
download an appropriate sqoop and unzip it to the hard disk. The so-called "appropriate" means that the version of sqoop should match the version of Hadoop. The author's Hadoop version is 1.03, and the downloaded sqoop version is 1.4.2< br />$ tar zvxf sqoop-1.4.2.bin__ Hadoop-1.0.0. Tar. GZ
download the appropriate jdbc driver and put the downloaded jdbc driver in the Lib folder of sqoop
import data
$sqoop import -- hive import -- connect jdbc:oracle:thin:@192.168.56.111 : 1521: dbname -- user name -- password password -- verb - M 1 -- table tablename
dbname: database name
User Name: user name
password: password
tablename: table name
- M: the number of concurrent processes importing data. The default is 4. If the imported data is not large, you might as well set it to 1, so that the import is faster. In general, sqoop uses primary keys to divide data evenly. Concurrent import can be set when the relevant split column, and so on, the specific approach to refer to the official document
If Oracle is installed on a remote computer, make sure that sqoop can ping the computer where Oracle is located. For example, if Oracle is installed on win7, you may need to turn off the firewall of win7. In addition, Oracle needs to be configured to be remotely accessible.