HCatLoader
//use default database
A = LOAD 'tablename' USING org.apache.hcatalog.pig.HCatLoader();
//specify database 'exampledb' and you could create the database and table using
//Hsql statements in Pig script after 0.10.
A = LOAD 'exampledb.tablename' USING org.apache.hcatalog.pig.HCatLoader();
because hive metastore is the same with Hcatalog, so the obove commands could be written as follows:
A = LOAD 'exampledb.tablename' USING org.apache.hive.hcatalog.pig.HCatLoader();
HCatStorer
//use default database STORE processed_data INTO 'tablename' USING org.apache.hcatalog.pig.HCatStorer(); //or using hive metastore class STORE processed_data INTO 'tablename' USING org.apache.hive.hcatalog.pig.HCatStorer();
//To add one new partition to a partitioned table, specify the partition value //in the store function. store z into 'web_data' using org.apache.hcatalog.pig.HCatStorer('datestamp=20110924');
When using pig with hcatalog, you should care about the type system.
References
https://cwiki.apache.org/confluence/display/Hive/HCatalog+LoadStore