Apache Cassandra static column 介绍与实战 Spark大数据博客 - https://www.iteblog.com Apache Cassandra static column 介绍与实战 假设我们有这样的场景：我们想在 Cassandra 中使用一张表记录用户基本信息（比如 email、密 码等）以及用户状态更新。我们知道，用户的基本信息一般很少会变动，但是状态会经常变化， ，Cassandra 引入了 static column。同一个 partition key 中被声明为 static 的列只有一个值的，也就是只存储一份。 如果想及时了 解Spark、Hadoop或者Hbase相关的文章，欢迎关注微信公共帐号：iteblog_hadoop 定义 static column 在表中将某个列定义为 STATIC 很简单，只需要在列的最后面加上 STATIC 关键字，具体如下： "email" text STATIC, "encrypted_password" blob STATIC, "body" text, PRIMARY KEY ("username", "id") ); iteblog_users_with_status_updates 表中我们将 email 和 encrypted_password 两个字段设置为 STATIC 了，这意味着同一个 username

第三届中国Rust开发者大会 Rustle: the first static analyzer for smart contracts in Rust Matthew Jiang Director of Security Team @ BlockSec Motivation Background Design 1 2 3 Capability Usability Conclusion with_attached_deposit(1) .with_static_gas(GAS_FOR_FT_TRANSFER_CALL) .ft_transfer_call(self.depositor.clone(), amount, None, "".to_string()) .then( ext_self::ext(env::current_account_id()) .with_static_gas(GAS_FOR_FT_RESOLVE_TRANSFER) documentation and samples is preferred Welcome to Contribute Usability Conclusion • Rustle is the first static analyzer for smart contracts in Rust and has been integrated into our workflow • Rustle supports

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 A Vindex maps column values to keyspace IDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . to move any records in other shards. The keyspace ID itself is computed using a function of some column in your data, such as the user ID. Vitess allows you to choose from a variety of functions (vindexes) VSchema allows you to associate table columns to sequence tables. If no value is specified for such a column, then VTGate will know to use the sequence table to generate a new value for it. VStream VStream

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120 A Vindex maps column values to keyspace IDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 394 Column List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . to move any records in other shards. The keyspace ID itself is computed using a function of some column in your data, such as the user ID. Vitess allows you to choose from a variety of functions (vindexes)

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141 A Vindex maps column values to keyspace IDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 458 Multi-Column Vindexes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 459 Column List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

• put_column() : Use column layout to output content. The content is arranged vertically • put_grid() : Output content using grid layout Here is an example by combining put_row() and put_column(): put_row([ put_row([ put_column([ put_code('A'), put_row([ put_code('B1'), None, # None represents the space between the output put_code('B2'), None, put_code('B3'), ]), put_code('C'), ]), None, put_code('D'), None the current popup window. Layout and Style put_row*† Use row layout to output content put_column*† Use column layout to output content put_grid* Output content using grid layout span Cross-cell content

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 A Vindex maps column values to keyspace IDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vindex. We will create 4 shards (-40, 40-80, 80-c0, c0-). The location will be denoted by a country column. Schema We will create 2 tables in this example. CREATE TABLE customer ( id int NOT NULL, fullname "customer": { "column_vindexes": [ { "columns": ["id", "country"], "name": "region_vdx" }, 14 This vindex uses a byte mapping of countries provided in a JSON file and combines that with the id column in the

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131 A Vindex maps column values to keyspace IDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 431 Column List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . to move any records in other shards. The keyspace ID itself is computed using a function of some column in your data, such as the user ID. Vitess allows you to choose from a variety of functions (vindexes)

• put_column() : Use column layout to output content. The content is arranged vertically • put_grid() : Output content using grid layout Here is an example by combining put_row() and put_column(): put_row([ put_row([ put_column([ put_code('A'), put_row([ put_code('B1'), None, # None represents the space between the output put_code('B2'), None, put_code('B3'), ]), put_code('C'), ]), None, put_code('D'), None the current popup window. Layout and Style put_row*† Use row layout to output content put_column*† Use column layout to output content put_grid* Output content using grid layout span Cross-cell content

• put_column() : Use column layout to output content. The content is arranged vertically • put_grid() : Output content using grid layout Here is an example by combining put_row() and put_column(): put_row([ put_row([ put_column([ put_code('A'), put_row([ put_code('B1'), None, # None represents the space between the output put_code('B2'), None, put_code('B3'), ]), put_code('C'), ]), None, put_code('D'), None the current popup window. Layout and Style put_row*† Use row layout to output content put_column*† Use column layout to output content put_grid* Output content using grid layout span Cross-cell content