Keyspace

Keyspace в NoSQL е обект, който обединява множество колони, които съдържат сходен тип информация (така наречените „column families“ – семейства от колони).^[1]^[2] Това е най-външният слой данни в цялостната схема.^[3] Оприличава се на така наречения схематичен модел при системите за управление на база данни.^[4] Обикновено приложенията имат по един keyspace.^[5]

Структура[редактиране | редактиране на кода]

Keyspace може да съдържа семейства колони или супер колони („super columns“). Всяка супер колона съдържа едно или няколко семейства колони, а всяка семейство – поне една колона с информация. Keyspace е най-високото ниво в класифицирания архив от данни.

Пример[редактиране | редактиране на кода]

Keyspace обект в Twitter.

<Keyspace Name="TwitterClone">
  <KeysCachedFraction>0.01</KeysCachedFraction>
  <ColumnFamily CompareWith="UTF8Type" Name="Users" />
  <ColumnFamily CompareWith="UTF8Type" Name="UserAudits" />
  <ColumnFamily CompareWith="UTF8Type" CompareSubcolumnsWith="TimeUUIDType" ColumnType="Super" Name="UserRelationships" />
  <ColumnFamily CompareWith="UTF8Type" Name="Usernames" />
  <ColumnFamily CompareWith="UTF8Type" Name="Statuses" />
  <ColumnFamily CompareWith="UTF8Type" Name="StatusAudits" />
  <ColumnFamily CompareWith="UTF8Type" CompareSubcolumnsWith="TimeUUIDType" ColumnType="Super" Name="StatusRelationships" />
</Keyspace>

Източници[редактиране | редактиране на кода]

↑ Ronald Mathies. Installing and using Apache Cassandra With Java Part 2 (Data model): Keyspaces // Sodeso – Software Development Solutions, 18 март 2010. Архивиран от оригинала на 2014-02-03. Посетен на 28 март 2011. Keyspaces are quite simple again, from an RDBMS point of view you can compare this to your schema, normally you have one per application. A keyspace contains the ColumnFamilies. Note, however, there is no relationship between the ColumnFamilies. They are just separate containers.
↑ Overview: Terminology/Abbreviations: Keyspace: // Cassandra Wiki. Архивиран от оригинала на 2013-07-23. Посетен на 31 март 2011. [A Keyspace] Contains multiple Column Families.
↑ Arin Sarkissian. WTF is a SuperColumn? An Intro to the Cassandra Data Model // Arin Sarkissian's blog, 23 август 2010. Архивиран от оригинала на 2010-12-31. Посетен на 25 март 2011. A Keyspace is the outer most grouping of your data. All your ColumnFamily‘s go inside a Keyspace. Your Keyspace will probably named after your application.
↑
Guy Harrison. Playing with Cassandra and Oracle // Guy Harrison's Web bits, 23 август 2010. Посетен на 25 март 2011. Terminology in NoSQL In Cassandra:
A Keyspace is like a schema

ColumnFamily is roughly like a table
It can be confusing, with each NoSQL database using terms differently from each other, and all of them using terms differently from RDBMS.
↑ Tutorial: Getting Started With Cassandra // myNoSQL. Посетен на 28 март 2011. Keyspaces are quite simple again, from an RDBMS point of view you can compare this to your schema, normally you have one per application. A keyspace contains the ColumnFamilies. Note however there is no relationship between the ColumnFamiliies, they are just separate containers.

[1] Ronald Mathies. Installing and using Apache Cassandra With Java Part 2 (Data model): Keyspaces // Sodeso – Software Development Solutions, 18 март 2010. Архивиран от оригинала на 2014-02-03. Посетен на 28 март 2011. Keyspaces are quite simple again, from an RDBMS point of view you can compare this to your schema, normally you have one per application. A keyspace contains the ColumnFamilies. Note, however, there is no relationship between the ColumnFamilies. They are just separate containers.

[2] Overview: Terminology/Abbreviations: Keyspace: // Cassandra Wiki. Архивиран от оригинала на 2013-07-23. Посетен на 31 март 2011. [A Keyspace] Contains multiple Column Families.

[3] Arin Sarkissian. WTF is a SuperColumn? An Intro to the Cassandra Data Model // Arin Sarkissian's blog, 23 август 2010. Архивиран от оригинала на 2010-12-31. Посетен на 25 март 2011. A Keyspace is the outer most grouping of your data. All your ColumnFamily‘s go inside a Keyspace. Your Keyspace will probably named after your application.

[terminology-4] Guy Harrison. Playing with Cassandra and Oracle // Guy Harrison's Web bits, 23 август 2010. Посетен на 25 март 2011. Terminology in NoSQL In Cassandra:
A Keyspace is like a schema

ColumnFamily is roughly like a table
It can be confusing, with each NoSQL database using terms differently from each other, and all of them using terms differently from RDBMS.

[5] A Keyspace is like a schema

[6] ColumnFamily is roughly like a table

[5] Tutorial: Getting Started With Cassandra // myNoSQL. Посетен на 28 март 2011. Keyspaces are quite simple again, from an RDBMS point of view you can compare this to your schema, normally you have one per application. A keyspace contains the ColumnFamilies. Note however there is no relationship between the ColumnFamiliies, they are just separate containers.

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