Abstract
This section describes the Table class, which
models a database table in the NDB API.
Parent class.
NdbDictionary
Child classes. None
Description.
The Table class represents a table in a MySQL
Cluster database. This class extends the
Object class, which in turn is an
inner class of the NdbDictionary
class.
It is possible using the NDB API to create tables independently of
the MySQL server. However, it is usually not advisable to do so,
since tables created in this fashion cannot be seen by the MySQL
server. Similarly, it is possible using Table
methods to modify existing tables, but these changes (except for
renaming tables) are not visible to MySQL.
Calculating Table Sizes. When calculating the data storage one should add the size of all attributes (each attribute consuming a minimum of 4 bytes) and well as 12 bytes overhead. Variable size attributes have a size of 12 bytes plus the actual data storage parts, with an additional overhead based on the size of the variable part. For example, consider a table with 5 attributes: one 64-bit attribute, one 32-bit attribute, two 16-bit attributes, and one array of 64 8-bit attributes. The amount of memory consumed per record by this table is the sum of the following:
8 bytes for the 64-bit attribute
4 bytes for the 32-bit attribute
8 bytes for the two 16-bit attributes, each of these taking up 4 bytes due to right-alignment
64 bytes for the array (64 * 1 byte per array element)
12 bytes overhead
This totals 96 bytes per record. In addition, you should assume an overhead of about 2% for the allocation of page headers and wasted space. Thus, 1 million records should consume 96 MB, and the additional page header and other overhead comes to approximately 2 MB. Rounding up yields 100 MB.
Methods. The following table lists the public methods of this class and the purpose or use of each method:
| Method | Purpose / Use |
|---|---|
Table() |
Class constructor |
~Table() |
Destructor |
addColumn() |
Adds a column to the table |
aggregate() |
Computes aggregate data for the table |
equal() |
Compares the table with another table |
getColumn() |
Gets a column (by name) from the table |
getDefaultNoPartitionsFlag() |
Checks whether the default number of partitions is being used |
getFragmentCount() |
Gets the number of fragments for this table |
getFragmentData() |
Gets table fragment data (ID, state, and node group) |
getFragmentDataLen() |
Gets the length of the table fragment data |
getFragmentNodes() |
Gets IDs of data nodes on which fragments are located |
getFragmentType() |
Gets the table's FragmentType
|
getFrmData() |
Gets the data from the table .FRM file |
getFrmLength() |
Gets the length of the table's .FRM file |
getHashMap() |
Gets the table's hash map. |
getKValue() |
Gets the table's KValue
|
getLinearFlag() |
Gets the current setting for the table's linear hashing flag |
getLogging() |
Checks whether logging to disk is enabled for this table |
getMaxLoadFactor() |
Gets the table's maximum load factor |
getMaxRows() |
Gets the maximum number of rows that this table may contain |
getMinLoadFactor() |
Gets the table's minimum load factor |
getName() |
Gets the table's name |
getNoOfColumns() |
Gets the number of columns in the table |
getNoOfPrimaryKeys() |
Gets the number of columns in the table's primary key. |
getObjectId() |
Gets the table's object ID |
getObjectStatus() |
Gets the table's object status |
getObjectType() |
Gets the table's object type
(Object::Type) |
getObjectVersion() |
Gets the table's object version |
getPartitionId() |
Gets a partition ID from a has value |
getPrimaryKey() |
Gets the name of the table's primary key |
getRangeListData() |
Gets a RANGE or LIST array |
getRangeListDataLen() |
Gets the length of the table RANGE or
LIST array |
getRowChecksumIndicator() |
Checks whether the row checksum indicator has been set |
getRowGCIIndicator() |
Checks whether the row GCI indicator has been set |
getTableId() |
Gets the table's ID |
getTablespace() |
Gets the tablespace containing this table |
getTablespaceData() |
Gets the ID and version of the tablespace containing the table |
getTablespaceDataLen() |
Gets the length of the table's tablespace data |
getTablespaceNames() |
Gets the names of the tablespaces used in the table fragments |
hasDefaultValues() |
Determine whether table has any columns using default values |
setDefaultNoPartitionsFlag() |
Toggles whether the default number of partitions should be used for the table |
setFragmentCount() |
Sets the number of fragments for this table |
setFragmentData() |
Sets the fragment ID, node group ID, and fragment state |
setFragmentType() |
Sets the table's FragmentType
|
setFrm() |
Sets the .FRM file to be used for this table |
setHashMap() |
Sets the table's hash map. |
setKValue() |
Set the KValue
|
setLinearFlag() |
Sets the table's linear hashing flag |
setLogging() |
Toggle logging of the table to disk |
setMaxLoadFactor() |
Set the table's maximum load factor (MaxLoadFactor) |
setMaxRows() |
Sets the maximum number of rows in the table |
setMinLoadFactor() |
Set the table's minimum load factor (MinLoadFactor) |
setName() |
Sets the table's name |
setObjectType() |
Sets the table's object type |
setRangeListData() |
Sets LIST and RANGE partition data |
setRowChecksumIndicator() |
Sets the row checksum indicator |
setRowGCIIndicator() |
Sets the row GCI indicator |
setStatusInvalid() |
|
setTablespace() |
Set the tablespace to use for this table |
setTablespaceData() |
Sets the tablespace ID and version |
setTablespaceNames() |
Sets the tablespace names for fragments |
validate() |
Validates the definition for a new table prior to creating it |
For detailed descriptions, signatures, and examples of use for each
of these methods, see Section 2.3.35.2, “Table Methods”.
Types.
The Table class defines a single public type
SingleUserMode.
Class diagram.
This diagram shows all the available methods of the
Table class:
