KDB: how do I do bulk insert in Java? - kdb

Question

I have a table with String columns "key1", "col1", "col2", "col3". I have a snippet below to test the bulk insert. When I run it, I don't get any error, yet I don't see any changes to the "test" table.
Did I miss something?
Object[][] data = new Object[4][];
ArrayList<String>[] rec = new ArrayList[4];
rec[0] = new ArrayList<String>();
rec[1] = new ArrayList<String>();
rec[2] = new ArrayList<String>();
rec[3] = new ArrayList<String>();
for (Integer i = 0; i < 10; i++) {
rec[0].add(i.toString() + i.toString() + i.toString());
rec[1].add(i.toString() + i.toString() + i.toString());
rec[2].add(i.toString() + i.toString() + i.toString());
rec[3].add(i.toString() + i.toString() + i.toString());
}
for (int i = 0; i < 4; i++) {
data[i] = rec[i].toArray(new Object[rec[i].size()]);
}
c.Dict dict = new c.Dict(Arrays.asList("key1", "col1", "col2", "col3").toArray(new String[4]), data);
c.Flip flip = new c.Flip(dict);
Object[] updStatement = new Object[] { ".u.upd", "test", flip };
conn.ks(updStatement);

Answer 1

Adding onto what you said, you want to be using the ks() method with 2 arguments.
From the javadoc given in the c.java class:
Use this to
* invoke a function in kdb+ which takes 2 arguments and does not return a value. e.g. to invoke f[x;y] use ks("f",x,y);
* to invoke a lambda, use ks("{x+y}",x,y);
The function .u.upd takes in 2 arguments and, by default, has the same signature as insert:
First argument is a symbol for the table name, which has the type String in Java
Second argument is the records which has the type Object[] in Java
The length of the Object[] in the second argument should be equal to the number of columns. Each Object in the Object[] should itself be an array that has a length equal to the number of records. The order of the inner arrays should be the same order as the columns, and the values of each inner array should have the matching type to the column type in kdb and have the same order as the records.
Your Object[] should look like:
new Object[]{
new Object[]{row1col1, row2col1, /*..., */ rowNcol1},
new Object[]{row1col2, row2col2, /*..., */ rowNcol2},
/* column 3 to column N-1 values */
new Object[]{row1colN, row2colN, /*..., */ rowNcolN}
}
And your ks() method call should look like:
conn.ks(".u.upd", "test", new Object[]{ /*.... */});