Alter Column Type

ALTER alter alter the name of the table structure of the name of the table ALTER TABLE ALTER TABLE ALTER TABLE statement is used to add, modify or delete columns in the existing table. sql alter table syntax To add a column to a table, use the following syntax: alter table table_name add column_name datatype To delete a column in a table, use the following syntax: alter table table _...

Hive in the official document of the query language has a very detailed description, please refer to: http://wiki.apache.org/hadoop/Hive/LanguageManual, most of the content of this article is translated from this page, Some of the things that need to be noted during the use process are added. Create tablecreate [EXTERNAL] TABLE [IF not EXISTS] table_name [col_name data_t ...

Http://www.aliyun.com/zixun/aggregation/13713.html ">hbase is a distributed, column-oriented open source database, rooted in a Google paper BigTable: A distributed storage system of structured data. HBase is an open-source implementation of Google BigTable, using Hadoop HDFs as its file storage system, using Hadoop mapreduce to handle ...

mysql tutorial to modify the table / field to add / delete table index create table test (blob_col blob, index (blob_col (10))); In mysql 5.1, myisam and innodb table prefix can reach 1000 bytes long. Note that the prefix limit should be measured in bytes, while the prefix length in the create table statement is interpreted as the number of characters. Must be considered when specifying the prefix length for columns that use multi-byte character sets. ...

If a computer manufacturer, its database holds machine and accessories product information. The table used to save the whole product information is called pc; the table used to save the parts supply information is called parts. There is a field in the pc table, used to describe the type of CPU used in this computer; there is a field in the parts table, the description of the CPU model, we can think of it as a list of all CPU models. Obviously, the CPU used by this manufacturer must be a model that exists in the supply information sheet. At this time, two tables ...

Intermediary trading http://www.aliyun.com/zixun/aggregation/6858.html ">seo diagnose Taobao guest cloud host technology Hall sometimes some of us are too focused on the inner chain of the site and the construction of the outside chain, 　　But ignore the site's most basic internal optimization work, and these optimization work if we do not do a good job, often like building a house, the foundation did not play in prison, think of the house how high and big the same reason! Recently I used ...

The complete collection of SQL statement operations deserves to be permanently stored the following statements are part of the MSSQL statement and are not available in Access. SQL classification: ddl-data Definition language (create,alter,drop,declare) dml-Data Manipulation Language (Select,delete,update,insert) dcl-Data Control Language (Grant,revoke, Commit,rollback first, briefly introduce the basic statement: 1, Description: Create number ...

Hive data type 1. Basic type Integer type: Tinyint,smallint,int,bigint, the above types correspond to the Byte,short,int,long in Java respectively. Decimal Type: Float,double Boolean type: Boolean string type: String,varchar,char 2. Complex Type Array,map,struct,timestamp (DATE) Common ...

Since the installation has been installed well hypertable, the Iron strike experience hql. Prepare the experimental data. hadoop@hadoop:~$ gunzip access.tsv.gz hadoop@hadoop:~$ mv ACCESS.TSV ~/hypertable/0.9.2.5/examples/hql_ tutorial/hadoop@hadoop:~$ CD ~/hypertable/0 ....

In this lesson, we want to learn how to increase the intelligent processing capacity of the Web page. Basic functions Welcome to the third and final lesson of this tutorial. If you've learned the first and second lessons, you've mastered the basics of installing and programming MySQL and PHP. Here are some of the other functions of PHP that might be useful to you and make your development process simpler. 　　First, let's look at the document. You should know some basic concepts of the header file, right? The header file is an external file whose contents are included in the main program. ...