SQL vs Cassandra数据类型映射

Question

我将一些数据类型从SQL服务器映射到cassandra，例如int到bigint，real到float，varchar到text。我在哪里可以获得从SQL服务器到cassandra的映射？

Answer 1

查看与CQL Data Types相比较的SQL Server Data Types描述，这里有一些映射，但是没有保证（考虑到CQL数据类型参考中的拼写错误并不过分自信）它们是准确的。

比较不考虑SQL Server上用于更改数据类型表示的设置，例如具有字符数据类型的排序规则集，或者您如何转换并将此数据传递给SQL Server。

我根据可由两种类型表示的值进行比较。密切关注评论。

CQL Data Type |   Match?  | SQL Server Data Type | Comment
-------------------------------------------------------------------------------------
list               N        none                   A collection; no native SQL equivalent. Perhaps sql_variant or XML could be used but operations on list in CQL wouldn't apply in SQL Server. Custom data types and CLR integrations would most likely be required
map                N        none                   Similar to above except as of SQL Server 2016, [JSON Data](https://msdn.microsoft.com/en-gb/library/dn921897.aspx) handling has been introduced so it's possible it could parse CQL maps
set                N        none                   "

int                Y        int                    Both represent 32-bit signed integers
bigint             Y        bigint                 Both represent 64-bit signed integers
varint             ?        smallint               Not clear if varint storage size will change, so if precision was -32768 to 32767, would it take 2 bytes? Also, if varint has values outside of smallint range, you may run into overflow errors. From smallint to varint, there's no indication in the above links
varint             ?        tinyint                Similar to above except if precision was 0 to 255, would it take 1 bytes?

float              Y        float

decimal            ?        decimal                Not clear of the precision and scaling limits of CQL decimal

ascii              ?        char, varchar          Not clear this mapping is accurate, more an assumption. Limits and conversion behaviour are not known
text               ?        ntext                  Based on UTF-8 encoding and that CQL seems to have varchar/text as does SQL. So it's likely text represents larger length text strings
varchar            ?        nchar, nvarchar        Based on UTF-8 encoding supported by both. Not clear what varchar limits are or the conversion behaviour

timestamp          ?        datetime               Not clear what timestamp limits are or the conversion behaviour

boolean            ?        bit                    Not clear on conversion behaviour

blob               ?        binary, varbinary      Not clear what the limits are on length of a CQL blob

uuid               ?        uniqueidentifier       uuid follows standard UUID format, most likely 128 bits (16 bytes) which is the same storage size as uniqueidentifier. Not clear on the conversion behaviour