深入浅出cassandra 3 例子背后的模型,深入浅出cassandra
深入浅出cassandra 3 例子背后的模型
在我们操作数据的代码中:
String table = "Keyspace1";
String row = "row007";
ColumnPath col = new ColumnPath("Standard1", null, "ahuaxuan".getBytes());
cassandraClient.insert(table, row, col, " first cassandra sample of ahuaxuan".getBytes(), 1, 1);
public static void main(String[] args) throws TException, TimedOutException, InvalidRequestException, UnavailableException, NotFoundException {
init();
String table = "Keyspace1";
String row = "row007";
ColumnPath col = new ColumnPath("Standard1", null, "ahuaxuan".getBytes());
ColumnPath col2 = new ColumnPath("Standard2", null, "ahuaxuan".getBytes());
cassandraClient.insert(table, row, col, " first cassandra sample of ahuaxuan".getBytes(), 3, 1);
cassandraClient.insert(table, row, col2, " second cassandra sample of ahuaxuan ".getBytes(), 4, 1);
Column column = cassandraClient.get(table, row, col, 1).column;
Column column2 = cassandraClient.get(table, row, col2, 1).column;
System.out.println("read row " + row);
System.out.println("column name: " + new String(column.name));
System.out.println("column value" + ": " + new String(column.value));
System.out.println("column timestamp" + ":" + (column.timestamp));
System.out.println("\r\nread row " + row);
System.out.println("column name: " + new String(column2.name));
System.out.println("column value" + ": " + new String(column2.value));
System.out.println("column timestamp" + ": " + (column2.timestamp));
}
第一次放到Keyspace1--row007--Standard1中,列名为ahuaxuan,列值为first cassandra sample of ahuaxuan,timestamp为3,
接着我更新Keyspace1--row007--Standard1中,列名为ahuaxuan,列值为second cassandra sample of ahuaxuan,timestamp为2
结果更新不成功,但是如果我把timestamp改成4,更新可以成功。
如上图所示
这
是一个存储Web网页的范例列表片断。行名是一个反向URL{即com.cnn.www}。contents列族{原文用
family,译为族,详见列族} 存放网页内容,anchor列族存放引用该网页的锚链接文本。CNN的主页被Sports
Illustrater{即所谓SI,CNN的王牌体育节目}和MY-look的主页引用,因此该行包含了名叫“anchor:cnnsi.com”和
“anchhor:my.look.ca”的列。每个锚链接只有一个版本{由时间戳标识,如t9,t8};而contents列则有三个版本,分别由时间
戳t3,t5,和t6标识。
本站文章为和通数据库网友分享或者投稿,欢迎任何形式的转载,但请务必注明出处.
同时文章内容如有侵犯了您的权益,请联系QQ:970679559,我们会在尽快处理。