edu.berkeley.cs186.database.table

Class Table

java.lang.Object

edu.berkeley.cs186.database.table.Table

All Implemented Interfaces:

Closeable, AutoCloseable, Iterable<Record>

public class Table
extends Object
implements Iterable<Record>, Closeable

A database table. Allows the user to add, delete, update, and get records. A table has an associated schema, stats, and page allocator. The first page in the page allocator is a header page that serializes the schema, and each subsequent page is a data page containing the table records. Properties: `schema`: the Schema (column names and column types) for this table `freePages`: a set of page numbers that correspond to allocated pages with free space `stats`: the TableStats for this table `allocator`: the PageAllocator for this table `tableName`: name of this table `numEntriesPerPage`: number of records a data page of this table can hold `pageHeaderSize`: physical size (in bytes) of a page header slot bitmap `numRecords`: number of records currently contained in this table

Field Summary

Fields

Modifier and Type	Field and Description
static String	FILENAME_EXTENSION
static String	FILENAME_PREFIX

Constructor Summary

Constructors

Constructor and Description
Table(Schema schema, String tableName)
Table(Schema schema, String tableName, String filenamePrefix) This constructor is used for creating a table in some specified directory.
Table(String tableName)
Table(String tableName, String filenamePrefix)

Method Summary

Methods

Modifier and Type	Method and Description
RecordID	addRecord(List<DataBox> values) Adds a new record to this table.
void	close()
Record	deleteRecord(RecordID rid) Deletes the record specified by rid from the table.
int	getNumEntriesPerPage()
Record	getRecord(RecordID rid) Retrieves a record from the table.
Schema	getSchema()
Iterator<Record>	iterator()
Record	updateRecord(List<DataBox> values, RecordID rid) Updates an existing record with new values and returns the old version of the record.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

FILENAME_PREFIX

public static final String FILENAME_PREFIX

See Also:

Constant Field Values

FILENAME_EXTENSION

public static final String FILENAME_EXTENSION

See Also:

Constant Field Values

Constructor Detail

Table

public Table(String tableName)

Table

public Table(String tableName,
     String filenamePrefix)

Table

public Table(Schema schema,
     String tableName)

Table

public Table(Schema schema,
     String tableName,
     String filenamePrefix)

This constructor is used for creating a table in some specified directory.

Parameters:

schema - the schema for this table

tableName - the name of the table

filenamePrefix - the prefix where the table's files will be created

Method Detail

close

public void close()

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

iterator

public Iterator<Record> iterator()

Specified by:

iterator in interface Iterable<Record>

addRecord

public RecordID addRecord(List<DataBox> values)
                   throws DatabaseException

Adds a new record to this table. The record should be added to the first free slot of the first free page if one exists, otherwise a new page should be allocated and the record should be placed in the first slot of that page. Recall that a free slot in the slot bitmap means the bit is set to 0. Make sure to update this.stats, this.freePages, and this.numRecords as necessary.

Parameters:

values - the values of the record being added

Returns:

the RecordID of the added record

Throws:

DatabaseException - if the values passed in to this method do not correspond to the schema of this table

deleteRecord

public Record deleteRecord(RecordID rid)
                    throws DatabaseException

Deletes the record specified by rid from the table. Make sure to update this.stats, this.freePages, and this.numRecords as necessary.

Parameters:

rid - the RecordID of the record to delete

Returns:

the Record referenced by rid that was removed

Throws:

DatabaseException - if rid does not correspond to a valid record

getRecord

public Record getRecord(RecordID rid)
                 throws DatabaseException

Retrieves a record from the table.

Parameters:

rid - the RecordID of the record to retrieve

Returns:

the Record referenced by rid

Throws:

DatabaseException - if rid does not correspond to a valid record

updateRecord

public Record updateRecord(List<DataBox> values,
                  RecordID rid)
                    throws DatabaseException

Updates an existing record with new values and returns the old version of the record. Make sure to update this.stats as necessary.

Parameters:

values - the new values of the record

rid - the RecordID of the record to update

Returns:

the old version of the record

Throws:

DatabaseException - if rid does not correspond to a valid record or if the values do not correspond to the schema of this table

getNumEntriesPerPage

public int getNumEntriesPerPage()

getSchema

public Schema getSchema()