The difference between hbase and relational database

What is the problem that HBase can solve relative to relational databases?

The difference between HBase and relational data is actually the advantages and disadvantages of relational database and HBase.

The shortcomings of relational databases:

1) Expansion difficulties

2) Maintenance complexity

HBase is the problem of resolving scalable lines. Linear scalability is achieved by simply adding nodes. SQL is not supported.

For most people who do technology, we know what our traditional database looks like, as shown in the figure below, the object we operate on is the row. That is, additions, deletions, and changes are considered objects.

1. Introduction of traditional database addition and deletion

Let's take mysql as an example:

Insert data

Mysql "INSERT INTO blog_user (`user_Name`,`user_Password`,`user_emial`)VALUES ('aboutyun','aboutyun', '');

delete data:

Mysql" delete from blog_user where user_name="aboutyun";

2. Nosql database added delete introduction

Take hbase as an example:

Create a table:

Create 'blog_user', 'userInfo'

Insert data

This is the key point and a place that many people don't understand easily.

Hbase(main):012:0" put'blog_user','','userInfo:user_Name','aboutyun'

0 row(s) in 1.7530 seconds

We saw above

What is shown in 1 is that we don't have any in the traditional data block. This is unique to nosql. It is a rowkey, which is the system's own and is the unique identifier of a record in nosql. But this unique identifier is different from our traditional database. As shown in Figure 1, "Record 1" is rowkey.

2 shows the column user_Name we inserted, which is also the most difficult to understand, the column can be inserted. And its 'value' is 3 or 'aboutyun'

We inserted the column, let's take a look at the effect:

Let me explain the above meaning:

we will see

1 is rowkey, insert data '',

2 is the name of the column below the column user_Name

3 We did not add this column family in the design, so this is the system's own, this is the recording operation time, put it in hbase in the form of timestamp.

4 is the value of the user_Name we inserted

Below we are inserting the password:

1. hbase(main):015:0" put'blog_user','','userInfo:user_Password','aboutyun'

Check the results again:

1. hbase(main):016:0" scan 'blog_user'

2. ROW COLUMN+CELL

3. column=userInfo:user_Name, TImestamp=1400663775901, value=aboutyun

4. column=userInfo:user_Password, TImestamp=1400665203430, value=aboutyun

5. 1 row(s) in 0.0390 seconds

At this point, we see two rows of records, the traditional data block thinks this is two rows of data, for nosql, this is a record.

Delete column data

Delete data is divided into delete columns and delete records

1. Delete the column

Deleted inside, not deleted

Delete 'blog_user','','userInfo:user_Password'

From the above we see that the column has been deleted.

2. Delete the record:

1. deleteall 'blog_user',''

2. This is the result displayed before deleting, here is already

Deleted result

For traditional databases, adding columns is very large for a project. But for nosql, inserting columns and deleting columns is similar to adding records and deleting records in a traditional database.

What are the basic characteristics of HBase?

HBase is an open source implementation of bigtable similar to google, with the following characteristics:

1) Above HDFS

2) Distributed database based on column storage

3) Used to read and write large-scale data sets in real time

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