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Using wide table support for ASE 12.5 and later
Adaptive Server version 12.5 and later offers limits and parameters that are
larger than in previous versions of the database server. For example:
• Tables can contain 1,024 columns.
• Varchar and varbinary columns can contain more than 255 bytes of data.
• You can send and retrieve up to 2,048 parameters when invoking stored
procedures or inserting data into tables.
To ensure that jConnect requests wide table support from the database,
jConnect 6.0 and later users must make sure that JCONNECT_VERSION = 6
the default setting.
Note jConnect continues to work with an Adaptive Server version 12.5 and
later if you set the version to earlier than JCONNECT_VERSION = 6.
However, if you try selecting from a table that requires wide table support to
fully retrieve the data, you may encounter unexpected errors or data truncation.
You can also set the JCONNECT_VERSION = 6 or later, when you access data
from a Sybase server that does not support wide tables. In this case, the server
simply ignores your request for wide table support.
In addition to the larger number of columns and parameters, wide table support
offers an extra benefit for jConnect users—a greater amount of
ResultSetMetaData. For example, in versions of jConnect earlier than 6.0, the
ResultSetMetaData methods getCatalogName, getSchemaName, and
getTableName all returned “Not Implemented” SQLExceptions because that
metadata was not supplied by the server. When you enable wide table support,
the server now sends back this information, and the three methods return useful
information.
[ 本帖最后由 xn_sung 于 2009-1-19 14:39 编辑 ] |
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发表于 2009-01-19 11:40
