org.apache.pig.piggybank.storage
Class DBStorage

java.lang.Object
  extended by org.apache.pig.StoreFunc
      extended by org.apache.pig.piggybank.storage.DBStorage
All Implemented Interfaces:
StoreFuncInterface

public class DBStorage
extends StoreFunc


Field Summary
protected  ResourceSchema schema
           
 
Constructor Summary
DBStorage(String driver, String jdbcURL, String insertQuery)
           
DBStorage(String driver, String jdbcURL, String user, String pass, String insertQuery)
           
DBStorage(String driver, String jdbcURL, String user, String pass, String insertQuery, String batchSize)
           
 
Method Summary
 void checkSchema(ResourceSchema s)
          Set the schema for data to be stored.
 org.apache.hadoop.mapreduce.OutputFormat getOutputFormat()
          Return the OutputFormat associated with StoreFunc.
 void prepareToWrite(org.apache.hadoop.mapreduce.RecordWriter writer)
          Initialise the database connection and prepared statement here.
 void putNext(Tuple tuple)
          Write the tuple to Database directly here.
 void setStoreFuncUDFContextSignature(String signature)
          This method will be called by Pig both in the front end and back end to pass a unique signature to the StoreFunc which it can use to store information in the UDFContext which it needs to store between various method invocations in the front end and back end.
 void setStoreLocation(String location, org.apache.hadoop.mapreduce.Job job)
          Communicate to the storer the location where the data needs to be stored.
protected  int sqlDataTypeFromPigDataType(byte pigDataType)
           
 
Methods inherited from class org.apache.pig.StoreFunc
cleanupOnFailure, cleanupOnFailureImpl, cleanupOnSuccess, relToAbsPathForStoreLocation, warn
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

schema

protected ResourceSchema schema
Constructor Detail

DBStorage

public DBStorage(String driver,
                 String jdbcURL,
                 String insertQuery)

DBStorage

public DBStorage(String driver,
                 String jdbcURL,
                 String user,
                 String pass,
                 String insertQuery)
          throws SQLException
Throws:
SQLException

DBStorage

public DBStorage(String driver,
                 String jdbcURL,
                 String user,
                 String pass,
                 String insertQuery,
                 String batchSize)
          throws RuntimeException
Throws:
RuntimeException
Method Detail

putNext

public void putNext(Tuple tuple)
             throws IOException
Write the tuple to Database directly here.

Specified by:
putNext in interface StoreFuncInterface
Specified by:
putNext in class StoreFunc
Parameters:
tuple - the tuple to store.
Throws:
IOException - if an exception occurs during the write

sqlDataTypeFromPigDataType

protected int sqlDataTypeFromPigDataType(byte pigDataType)

getOutputFormat

public org.apache.hadoop.mapreduce.OutputFormat getOutputFormat()
                                                         throws IOException
Description copied from class: StoreFunc
Return the OutputFormat associated with StoreFunc. This will be called on the front end during planning and on the backend during execution.

Specified by:
getOutputFormat in interface StoreFuncInterface
Specified by:
getOutputFormat in class StoreFunc
Returns:
the OutputFormat associated with StoreFunc
Throws:
IOException - if an exception occurs while constructing the OutputFormat

prepareToWrite

public void prepareToWrite(org.apache.hadoop.mapreduce.RecordWriter writer)
                    throws IOException
Initialise the database connection and prepared statement here.

Specified by:
prepareToWrite in interface StoreFuncInterface
Specified by:
prepareToWrite in class StoreFunc
Parameters:
writer - RecordWriter to use.
Throws:
IOException - if an exception occurs during initialization

setStoreLocation

public void setStoreLocation(String location,
                             org.apache.hadoop.mapreduce.Job job)
                      throws IOException
Description copied from class: StoreFunc
Communicate to the storer the location where the data needs to be stored. The location string passed to the StoreFunc here is the return value of StoreFunc.relToAbsPathForStoreLocation(String, Path) This method will be called in the frontend and backend multiple times. Implementations should bear in mind that this method is called multiple times and should ensure there are no inconsistent side effects due to the multiple calls. StoreFunc.checkSchema(ResourceSchema) will be called before any call to StoreFunc.setStoreLocation(String, Job).

Specified by:
setStoreLocation in interface StoreFuncInterface
Specified by:
setStoreLocation in class StoreFunc
Parameters:
location - Location returned by StoreFunc.relToAbsPathForStoreLocation(String, Path)
job - The Job object
Throws:
IOException - if the location is not valid.

setStoreFuncUDFContextSignature

public void setStoreFuncUDFContextSignature(String signature)
Description copied from class: StoreFunc
This method will be called by Pig both in the front end and back end to pass a unique signature to the StoreFunc which it can use to store information in the UDFContext which it needs to store between various method invocations in the front end and back end. This method will be called before other methods in StoreFunc. This is necessary because in a Pig Latin script with multiple stores, the different instances of store functions need to be able to find their (and only their) data in the UDFContext object. The default implementation is a no-op.

Specified by:
setStoreFuncUDFContextSignature in interface StoreFuncInterface
Overrides:
setStoreFuncUDFContextSignature in class StoreFunc
Parameters:
signature - a unique signature to identify this StoreFunc

checkSchema

public void checkSchema(ResourceSchema s)
                 throws IOException
Description copied from class: StoreFunc
Set the schema for data to be stored. This will be called on the front end during planning if the store is associated with a schema. A Store function should implement this function to check that a given schema is acceptable to it. For example, it can check that the correct partition keys are included; a storage function to be written directly to an OutputFormat can make sure the schema will translate in a well defined way. Default implementation is a no-op.

Specified by:
checkSchema in interface StoreFuncInterface
Overrides:
checkSchema in class StoreFunc
Parameters:
s - to be checked
Throws:
IOException - if this schema is not acceptable. It should include a detailed error message indicating what is wrong with the schema.


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