[JDBC] UpdateableResultSet patch (not finished yet!)
Hello, I have, for some time, now, been working on the updateable resultset class. Please have a look at http://www.miranda.org/~ola/jdbcupr.diff, and let me know what you think. It is only rudimentary at the moment. Things to consider: * Parsing of query. Very hackish at the moment. * Concurrency check. Things that need work: * Documentation * Inserting - nothing done as of yet. * The test case needs to be more elaborate. Ola -- Ola Sundell [EMAIL PROTECTED] - [EMAIL PROTECTED] - [EMAIL PROTECTED] http://miranda.org/~ola ---(end of broadcast)--- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
Re: [JDBC] UpdateableResultSets and concurrency.
On Sun, 8 Jul 2001, Ola Sundell wrote: On Tue, 26 Jun 2001, Dave Cramer wrote: Ola, How are you planning on determining if the underlying data has been changed by some other process? There is a system column called xmin which can be used, however you will have to add it to the select. Dave At first, I will let the backend handle any and all problems that might occur. I will simply forward any exceptions I get, and let the overlying code handle the problems. I checked the MySQL driver, and that is how they are doing it. I wonder how it works with non-free databases. Does anyone here know? Silly me. When I woke up this morning, I realised that MySQL doesn't support transactions. I re-read the JDBC spec, and I will do a simple optimistic concurrency control by starting a transaction, re-reading the row and checking the values. mvh Ola -- Ola Sundell [EMAIL PROTECTED] - [EMAIL PROTECTED] - [EMAIL PROTECTED] http://miranda.org/~ola ---(end of broadcast)--- TIP 5: Have you checked our extensive FAQ? http://www.postgresql.org/users-lounge/docs/faq.html
[JDBC] UpdateableResultSets and concurrency.
On Tue, 26 Jun 2001, Dave Cramer wrote: Ola, How are you planning on determining if the underlying data has been changed by some other process? There is a system column called xmin which can be used, however you will have to add it to the select. Dave At first, I will let the backend handle any and all problems that might occur. I will simply forward any exceptions I get, and let the overlying code handle the problems. I checked the MySQL driver, and that is how they are doing it. I wonder how it works with non-free databases. Does anyone here know? Ola -- Ola Sundell [EMAIL PROTECTED] - [EMAIL PROTECTED] - [EMAIL PROTECTED] http://miranda.org/~ola ---(end of broadcast)--- TIP 6: Have you searched our list archives? http://www.postgresql.org/search.mpl
[JDBC] getTableName() in ResultSetMetaData
Hello. I've been hacking a bit, and I've come to a conclusion, which may or may not be true; to implement quite a number of things in the ResultSetMetaData class, we'll need to implement getTableName(int colnum), and to implement getTable(), we need additional information from the backend, like the relid from pg_class, where relid is SELECT relid FROM pg_class WHERE relname = 'table_where_col_is_from', added to the Field class. It would, too, be good to include attnum from pg_attribute, too. This will also ease implementation of things like isAutoIncrement(int colnum), if you define auto incrementation as having a DEFAULT value which is read from a sequence that is incremented one step at a time. I really need this feature (and I want it to behave like I described, as you might have guessed :). An idea, to make the definition of a column which "auto increments", is to alter table pg_attribute add attisserial boolean, and then just set that, if the newly-created column is serial, and use the pg_attribute column to check whether it is auto incrementing, or not. Now, I know of two things that you probably will say: a) Feature freeze - not in 7.1 (naturally). I can understand that, and I can also, sorta, wait until 7.2 development starts...but I'd love to see this asap, naturall b) Postgresql doesn't really support auto incrementation. I know that, too, but I want, due to ejb-specific reasons, be able to gather information about whether the column is auto-incrementing, or not. I can, of course, write a small hack in my own app, but this seems much neater. :) OK, did that make sense at all? Ola -- --- Ola Sundell [EMAIL PROTECTED] - [EMAIL PROTECTED] - [EMAIL PROTECTED] http://miranda.org/~ola PGP key information: pub 1024/744E6D8D 2000/02/13 Ola Sundell [EMAIL PROTECTED] Key fingerprint = 8F CA 7C 6F EC 0D C0 23 1E 08 BF 32 FC 37 24 E3 ---(end of broadcast)--- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]
[JDBC] PATCH to org/postgresql/jdbc2/DatabaseMetaData.java
---
postgresql-7.1beta4/src/interfaces/jdbc/org/postgresql/jdbc2/DatabaseMetaData.java
Mon Jan 29 03:53:56 2001
+++
postgresql-7.1beta4-new/src/interfaces/jdbc/org/postgresql/jdbc2/DatabaseMetaData.java
Sat Feb 17 10:22:38 2001
@@ -1048,7 +1048,7 @@
/**
* Can statements remain open across commits? They may, but
* this driver cannot guarentee that. In further reflection.
- * we are talking a Statement object jere, so the answer is
+ * we are talking a Statement object here, so the answer is
* yes, since the Statement is only a vehicle to ExecSQL()
*
* @return true if they always remain open; false otherwise
@@ -2185,6 +2185,81 @@
);
}
+ private Vector importLoop(java.sql.ResultSet keyRelation) throws
SQLException {
+String s,s2;
+String origTable=null, primTable=new String(""), schema;
+int i;
+Vector v;
+
+s=keyRelation.getString(1);
+s2=s;
+System.out.println(s);
+v=new Vector();
+for (i=0;;i++) {
+ s=s.substring(s.indexOf("\\000")+4);
+ if (s.compareTo("")==0) {
+ System.out.println();
+ break;
+ }
+ s2=s.substring(0,s.indexOf("\\000"));
+ switch (i) {
+ case 0:
+ origTable=s2;
+ break;
+ case 1:
+ primTable=s2;
+ break;
+ case 2:
+ schema=s2;
+ break;
+ default:
+ v.add(s2);
+ }
+ }
+
+ java.sql.ResultSet rstmp=connection.ExecSQL("select * from
"+origTable+" where 1=0");
+ java.sql.ResultSetMetaData origCols=rstmp.getMetaData();
+
+ String stmp;
+ Vector tuples=new Vector();
+ byte tuple[][];
+
+ // the foreign keys are only on even positions in the Vector.
+ for (i=0;iv.size();i+=2) {
+stmp=(String)v.elementAt(i);
+
+for (int j=1;j=origCols.getColumnCount();j++) {
+ if (stmp.compareTo(origCols.getColumnName(j))==0) {
+ tuple=new byte[14][0];
+
+ for (int k=0;k14;k++)
+ tuple[k]=null;
+
+ //PKTABLE_NAME
+ tuple[2]=primTable.getBytes();
+ //PKTABLE_COLUMN
+ stmp=(String)v.elementAt(i+1);
+ tuple[3]=stmp.getBytes();
+ //FKTABLE_NAME
+ tuple[6]=origTable.getBytes();
+ //FKCOLUMN_NAME
+ tuple[7]=origCols.getColumnName(j).getBytes();
+ //KEY_SEQ
+ tuple[8]=Integer.toString(j).getBytes();
+
+ tuples.add(tuple);
+
+ System.out.println(origCols.getColumnName(j)+
+ ": "+j+" - "+primTable+": "+
+ (String)v.elementAt(i+1));
+ break;
+ }
+}
+ }
+
+ return tuples;
+ }
+
/**
* Get a description of the primary key columns that are
* referenced by a table's foreign key columns (the primary keys
@@ -2238,8 +2313,39 @@
*/
public java.sql.ResultSet getImportedKeys(String catalog, String
schema, String table) throws SQLException
{
-// XXX-Not Implemented
-return null;
+// Added by Ola Sundell [EMAIL PROTECTED]
+// FIXME: error checking galore!
+java.sql.ResultSet rsret;
+Field f[]=new Field[14];
+byte tuple[][];
+
+f[0]=new Field(connection, "PKTABLE_CAT", iVarcharOid, 32);
+f[1]=new Field(connection, "PKTABLE_SCHEM", iVarcharOid, 32);
+f[2]=new Field(connection, "PKTABLE_NAME", iVarcharOid, 32);
+f[3]=new Field(connection, "PKCOLUMN_NAME", iVarcharOid, 32);
+f[4]=new Field(connection, "FKTABLE_CAT", iVarcharOid, 32);
+f[5]=new Field(connection, "FKTABLE_SCHEM", iVarcharOid, 32);
+f[6]=new Field(connection, "FKTABLE_NAME", iVarcharOid, 32);
+f[7]=new Field(connection, "FKCOLUMN_NAME", iVarcharOid, 32);
+f[8]=new Field(connection, "KEY_SEQ", iInt2Oid, 2);
+f[9]=new Field(connection, "UPDATE_RULE", iInt2Oid, 2);
+f[10]=new Field(connection, "DELETE_RULE", iInt2Oid, 2);
+f[11]=new Field(connection, "FK_NAME", iVarcharOid, 32);
+f[12]=new Field(connection, "PK_NAME", iVarcharOid, 32);
+f[13]=new Field(connection, "DEFERRABILITY", iInt2Oid, 2);
+
+java.sql.ResultSet rs=connection.ExecSQL("select t.tgargs "+
+ "from pg_class as c, pg_trigger as t "+
+ "where c.relname like '"+table+"' and
c.relfilenode=t.tgrelid");
+Vector tuples=new Vector();
+
+while (rs.next()) {
+ tuples.addAll(importLoop(rs));
+}
+
+rsret=new ResultSet(connection, f, tuples, "OK", 1);
+
+return rsret;
}
/**
