PostgreSQL JDBC - PreparedStatement.setXXX

Author

PreparedStatement.setXXX

Roberta Campo

2005-07-18, 7:23 am

We're moving from Postgresql7.4 to v.8.0.3,
with some problems rising from the strictness of the new driver
postgresql-8.0-311.jdbc3.jar.

We used to call a function f(integer[]) using
PreparedStatement.setString('{...}')
but now the types are not compatible.

How should we fix that ?

A. Using the setArray method :
This requires the implementation of the interface java.sql.Array :
- which methods are required in this case ?
- is there any available implementation of this class ? :)

B. Using the setObject(colnumber,
String, type ) method :
This should require less implementation than the Array, shouldn't it ?
- how to specify the type int[] ?

C. Using different drivers / protocol versions / ...

Thanks,
Roberta

Dave Cramer

2005-07-18, 9:23 am

Roberta,

You can force version 2 protocol with protocolVersion=2

or you can implement the Array interface.

For putting information into the db, I would imagine all you need to
implement is everything up to getResultSet()

Dave
On 18-Jul-05, at 7:55 AM, Roberta Campo wrote:

> We're moving from Postgresql7.4 to v.8.0.3,
> with some problems rising from the strictness of the new driver
> postgresql-8.0-311.jdbc3.jar.
>
> We used to call a function f(integer[]) using
> PreparedStatement.setString('{...}')
> but now the types are not compatible.
>
>
> How should we fix that ?
>
> A. Using the setArray method :
> This requires the implementation of the interface java.sql.Array :
> - which methods are required in this case ?
> - is there any available implementation of this class ? :)
>
> B. Using the setObject(colnumber,
String, type ) method :
> This should require less implementation than the Array, shouldn't it ?
> - how to specify the type int[] ?
>
> C. Using different drivers / protocol versions / ...
>
> Thanks,
> Roberta
>
>
>
> ---------------------------(end of
> broadcast)---------------------------
> TIP 6: explain analyze is your friend
>
>

Dave Cramer
davec@postgresintl.com
www.postgresintl.com
ICQ #14675561
jabber davecramer@jabber.org
ph (519 939 0336 )

sumit shah

2005-07-18, 9:23 am

Roberta:

Here is my utility code that implements java.sql.Array:

public static Array convertStringToPgSql
Array(final String[] s)
throws Exception {
if(s == null || s.length < 1) return null;
Array a = new Array() {
public String getBaseTypeName() {return "text";}
public int getBaseType() {return 0;}
public Object getArray() {return null;}
public Object getArray(Map<String, Class<?>> map) {return null;}
public Object getArray(long index, int count) {return null;}
public Object getArray(long index, int count, Map<String,
Class<?>> map) {return null;}
public ResultSet getResultSet() {return null;}
public ResultSet getResultSet(Map<String, Class<?>> map)
{return null;}
public ResultSet getResultSet(long index, int count) {return
null;}
public ResultSet getResultSet(long index, int count,
Map<String, Class<?>> map) {return null;}

public String toString() {
String p = "{";
if(s.length == 0) {
} else {
for(int i = 0; i < s.length - 1; i++) p += s[i] + ",";
p += "'" + s[s.length - 1] + "'";
}
p+="}";
return p;
}
};
return a;
}

public static Array convertIntegerToPgSq
lArray(final int[] p) {
if(p == null || p.length < 1) return null;
Array a = new Array() {
public String getBaseTypeName() {return "int4";}
public int getBaseType() {return 0;}
public Object getArray() {return null;}
public Object getArray(Map<String, Class<?>> map) {return null;}
public Object getArray(long index, int count) {return null;}
public Object getArray(long index, int count, Map<String,
Class<?>> map) {return null;}
public ResultSet getResultSet() {return null;}
public ResultSet getResultSet(Map<String, Class<?>> map)
{return null;}
public ResultSet getResultSet(long index, int count) {return
null;}
public ResultSet getResultSet(long index, int count,
Map<String, Class<?>> map) {return null;}

public String toString() {
String fp = "{";
if(p.length == 0) {
} else {
for(int i = 0; i < p.length - 1; i++) fp += p[i] + ",";
fp += p[p.length - 1];
}
fp+="}";
return fp;
}
};
return a;
}

On Jul 18, 2005, at 6:52 AM, Dave Cramer wrote:

> Roberta,
>
> You can force version 2 protocol with protocolVersion=2
>
> or you can implement the Array interface.
>
> For putting information into the db, I would imagine all you need
> to implement is everything up to getResultSet()
>
> Dave
> On 18-Jul-05, at 7:55 AM, Roberta Campo wrote:
>
>
>
>
> Dave Cramer
> davec@postgresintl.com
> www.postgresintl.com
> ICQ #14675561
> jabber davecramer@jabber.org
> ph (519 939 0336 )
>

Oliver Jowett

2005-07-18, 8:24 pm

Roberta Campo wrote:

> A. Using the setArray method :
> This requires the implementation of the interface java.sql.Array :
> - which methods are required in this case ?
> - is there any available implementation of this class ? :)

Someone else replied to this with an implementation..

The driver's Array support is pretty bad currently. It will only work if
the Array implementation implements:

- getBaseTypeName() returns the underlying postgresql type name ("int")
- toString() returns a correctly-formatted array string ("{1,2,3}")

Proper support for arbitrary Array implementations (and bare arrays via
setObject) has been on my todo list for ages but it's no longer a high
priority for our application so I doubt I'll work on it any time soon :/

> B. Using the setObject(colnumber,
String, type ) method :
> This should require less implementation than the Array, shouldn't it ?
> - how to specify the type int[] ?

JDBC has no mechanism to specify a particular array type via a Types.*
constant unfortunately :(

> C. Using different drivers / protocol versions / ...

Using protocol version 2 as Dave Cramer suggests is a short-term fix but
you don't want to be using that in the longer term..

-O

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