xuemingqiang/mongo
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

WT-2360 Introduced a more complex join example to show nesting and disjunction.

Browse Source
This commit is contained in:
Don Anderson
2016-04-14 15:58:09 -04:00
parent 12e9a78a60
commit dce3b942e4
2 changed files with 130 additions and 22 deletions
Download Patch File Download Diff File Expand all files Collapse all files

76
examples/java/com/wiredtiger/examples/ex_schema.java
View File

@@ -76,7 +76,8 @@ public class ex_schema {
throws WiredTigerException
{
Connection conn;
Cursor cursor, cursor2, join_cursor, stat_cursor;
Cursor country_cursor, country_cursor2, cursor, join_cursor,
stat_cursor, subjoin_cursor, year_cursor;
Session session;
String country;
long recno, population;
@@ -343,18 +344,18 @@ public class ex_schema {
/* Open cursors needed by the join. */
join_cursor = session.open_cursor(
"join:table:poptable", null, null);
cursor = session.open_cursor(
country_cursor = session.open_cursor(
"index:poptable:country", null, null);
cursor2 = session.open_cursor(
year_cursor = session.open_cursor(
"index:poptable:immutable_year", null, null);
/* select values WHERE country == "AU" AND year > 1900 */
cursor.putKeyString("AU");
ret = cursor.search();
session.join(join_cursor, cursor, "compare=eq,count=10");
cursor2.putKeyShort((short)1900);
ret = cursor2.search();
session.join(join_cursor, cursor2,
country_cursor.putKeyString("AU");
ret = country_cursor.search();
session.join(join_cursor, country_cursor, "compare=eq,count=10");
year_cursor.putKeyShort((short)1900);
ret = year_cursor.search();
session.join(join_cursor, year_cursor,
"compare=gt,count=10,strategy=bloom");
/* List the values that are joined */
@@ -376,8 +377,61 @@ public class ex_schema {
ret = stat_cursor.close();
ret = join_cursor.close();
ret = cursor2.close();
ret = cursor.close();
ret = year_cursor.close();
ret = country_cursor.close();
/*! [Complex join cursors] */
/* Open cursors needed by the join. */
join_cursor = session.open_cursor(
"join:table:poptable", null, null);
subjoin_cursor = session.open_cursor(
"join:table:poptable", null, null);
country_cursor = session.open_cursor(
"index:poptable:country", null, null);
country_cursor2 = session.open_cursor(
"index:poptable:country", null, null);
year_cursor = session.open_cursor(
"index:poptable:immutable_year", null, null);
/*
* select values WHERE (country == "AU" OR country == "UK")
* AND year > 1900
*
* First, set up the join representing the country clause.
*/
country_cursor.putKeyString("AU");
ret = country_cursor.search();
ret = session.join(subjoin_cursor, country_cursor,
"operation=or,compare=eq,count=10");
country_cursor2.putKeyString("UK");
ret = country_cursor2.search();
ret = session.join(subjoin_cursor, country_cursor2,
"operation=or,compare=eq,count=10");
/* Join that to the top join, and add the year clause */
ret = session.join(join_cursor, subjoin_cursor, null);
year_cursor.putKeyShort((short)1900);
ret = year_cursor.search();
ret = session.join(join_cursor, year_cursor,
"compare=gt,count=10,strategy=bloom");
/* List the values that are joined */
while ((ret = join_cursor.next()) == 0) {
recno = join_cursor.getKeyRecord();
country = join_cursor.getValueString();
year = join_cursor.getValueShort();
population = join_cursor.getValueLong();
System.out.print("ID " + recno);
System.out.println( ": country " + country + ", year " + year +
", population " + population);
}
/*! [Complex join cursors] */
ret = join_cursor.close();
ret = subjoin_cursor.close();
ret = year_cursor.close();
ret = country_cursor.close();
ret = country_cursor2.close();
ret = conn.close(null);