一、下载安装
二、集群搭建
三、调优
四、客户端选择
五、Java Driver 1.0 for Apache Cassandra
Java classes to CQL3 data types
| CQL3 data type | Java type |
|---|---|
| ascii | java.lang.String |
| bigint | long |
| blob | java.nio.ByteBuffer |
| boolean | boolean |
| counter | long |
| decimal | java.math.BigDecimal |
| double | double |
| float | float |
| inet | java.net.InetAddress |
| int | int |
| list | java.util.List<T> |
| map | java.util.Map<K, V> |
| set | java.util.Set<T> |
| text | java.lang.String |
| timestamp | java.util.Date |
| timeuuid | java.util.UUID |
| uuid | java.util.UUID |
| varchar | java.lang.String |
| varint | java.math.BigInteger |
CQL
CQL Data Types
| CQL Type | Constants | Description |
|---|---|---|
| ascii | strings | US-ASCII character string |
| bigint | integers | 64-bit signed long |
| blob | blobs | Arbitrary bytes (no validation), expressed as hexadecimal |
| boolean | booleans | true or false |
| counter | integers | Distributed counter value (64-bit long) |
| decimal | integers, floats | Variable-precision decimal |
| double | integers | 64-bit IEEE-754 floating point |
| float | integers, floats | 32-bit IEEE-754 floating point |
| inet | strings | IP address string in IPv4 or IPv6 format* |
| int | integers | 32-bit signed integer |
| list | n/a | A collection of one or more ordered elements |
| map | n/a | A JSON-style array of literals: { literal : literal, literal : literal ... } |
| set | n/a | A collection of one or more elements |
| text | strings | UTF-8 encoded string |
| timestamp | integers, strings | Date plus time, encoded as 8 bytes since epoch |
| uuid | uuids | A UUID in format |
| timeuuid | uuids | Type 1 UUID only (CQL 3) |
| varchar | strings | UTF-8 encoded string |
| varint | integers | Arbitrary-precision integer |
*Used by python-cql driver and binary protocols.
六、异常
com.datastax.driver.core.exceptions.UnavailableException: Not enough replica available for query at consistency ONE (1 required but only 0 alive)
解决：
Bad Request: ORDER BY is only supported when the partition key is restricted by an EQ or an IN.
七、keyspace的两种类型与snitch集群解疑
八、cql语法