scruz-denodo opened a new issue, #1375:
URL: https://github.com/apache/arrow-java/issues/1375
### Describe the enhancement requested
# Describe the enhancement requested
The Flight SQL JDBC driver always prepares a statement on the server and
binds its parameters. It can exists servers implementing Flight SQL connection
interface which do not support the parameters binding process.
- they do not implement `CreatePreparedStatement`, or
- they can prepare a statement but cannot bind its parameters .
In those cases, the usage of `PreparedStatements` is not 100% usable.
One of the main problems of this is that thirdparty-tools using the JDBC
driver usually make use of `PreparedStatement` classes and there is no way for
overriding that behavior.
I have changes which I think they can be useful for this. They consist on
adding an optional mode in which the driver handles `PreparedStatement ` on the
client side:
- It keeps the statement text.
- It writes the parameter values into it as SQL literals, using a pluggable
`SqlDialect`.
- It runs the result as a plain query or update.
Statements prepared on the server keep their current behavior, and the
default behavior does not change.
## Proposed design
### Connection properties
- `disableServerPreparedStatements`: No statement is prepared on the server.
(disabled by default, so the current behavior is the default)
- `disableServerPreparedQueries`: Only queries are handled on the client.
Updates with parameters are still prepared on the server.
- `dialect `/ `dialectClass`: The SQL dialect used to write literals, chosen
by name through a registry or by class.
- `clientSideMetadataProbe`: Whether the first getMetaData() call asks the
server for the result columns.
### Dialects
- `SqlDialect` is an interface in which every method has an ANSI SQL
default, so a dialect overrides only what its database does differently.
- It is discovered through `ServiceLoader` and a `SqlDialectRegistry`.
- It covers literals for strings, numbers, binary values, dates, times,
timestamps, intervals, ``, arrays and rows.
- It classifies a statement as query or update by its first keyword.
- It produces the metadata probe by replacing every parameter marker with
NULL.
- A default `AnsiSqlDialect` which keeps all the defaults.
- `SqlParameterScanner `finds the `?` markers outside string literals,
quoted identifiers and comments. Dialects can tune it with lexical rules, for
example // comments.
### Value conversion
`SqlValueFactory` turns what JDBC and Avatica hand over for a parameter into
a small value model. The dialect implementations then deals with one
representation.
This issue is related with
[issue-62](https://github.com/apache/arrow-java/issues/62).
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