Creating Column Families
Explains how to create column families using either the Control System, the CLI, or the HBase shell.
About this task
There are several methods that you can use to create column families in HPE Ezmeral Data Fabric Database tables. To create column families, you must have the following permissions:
Creating Column Families Using the Control System
About this task
Procedure
-
Click:
- Take me to Add Column Family after creating a new table.
- Add Column Family from the All pane of Column Families tab under the table information page.
-
Specify the following properties in the Properties
pane of the Add Column Family page to set up a column
family, as needed. See the table below for information on fields shown under
the Properties pane of the Add Column
Family page.
Field Field Description Column Family Name The name of the column family. JSON Path The path to the column family in dotted notation. For example, suppose the table contained JSON documents that were of this general structure:
If you want to create a column family at the field{ "_id" : "ID", "a" : { "b" : { "c" : "value", }, "e" : "value" } }
d
nested withinb
, your new path would bea.b.d
.NOTEEnsure that the field at which you want to create the column family does not yet exist. If the field exists, it could become inaccessible after the column family is created.Compression The compression setting to use for the column family. Valid options are off
,lzf
,lz4
, andzlib
. The default setting is the same as the compression setting for the directory where the table is located.In Memory Determines whether preference is given to values of this column family for storage with row keys. Because row keys are cached in memory in preference to row data, column-family data that is stored inline with the row keys is also cached in memory. For all column families in a table together, up to 200 bytes of row data will be stored inline with each row key. Storing data inline with a row key might speed retrieval of the data from a column family because disk access can often be avoided. For each column family, up to 32 bytes can be stored inline with each row key even if this is disabled (No), but preference will be given to column families where this is enabled (Yes). A column family can have more than 32 bytes stored inline if this is enabled.
If the total number of bytes for all column families together exceeds 200 for a row, then preference for inclusion within the inline storage for that row is given to column families that have this enabled.
By default, this is enabled.NOTEAll of the data for a column family will be stored in-line with the row key, or none will be. If the contents in a column family for a particular row are larger than the maximum number of bytes that are allowed to be stored for that column family, no data will be stored in-line for that column family.Field Field Description Column Family Name The name of the column family. Version - Minimum — The minimum number of versions of column values to keep. The default is zero.
- Maximum — Maximum number of versions of column values to keep. The default is one.
Compression The compression setting to use for the column family. Valid options are off, lzf, lz4, and zlib. The default setting is the same as the compression setting for the directory where the table is located. Time-to-Live Specifies whether to purge data when the age of the data in this column family exceeds the value specified here. Data can remain forever or can be purged after specified amount of time (in seconds). Setting the value to 0 is equivalent to allowing data to remain indefinitely or forever. In Memory Determines whether preference is given to values of this column family for storage with row keys. Because row keys are cached in memory in preference to row data, column-family data that is stored inline with the row keys is also cached in memory. For all column families in a table together, up to 200 bytes of row data will be stored inline with each row key. Storing data inline with a row key might speed retrieval of the data from a column family because disk access can often be avoided. For each column family, up to 32 bytes can be stored inline with each row key even if this is disabled (No), but preference will be given to column families where this is enabled (Yes). A column family can have more than 32 bytes stored inline if this is enabled.
If the total number of bytes for all column families together exceeds 200 for a row, then preference for inclusion within the inline storage for that row is given to column families that have this enabled.
By default, this is enabled.NOTEAll of the data for a column family will be stored in-line with the row key, or none will be. If the contents in a column family for a particular row are larger than the maximum number of bytes that are allowed to be stored for that column family, no data will be stored in-line for that column family. -
(JSON Tables) Under the Security Policy pane, set
the security policy for the displayed table column family, as needed:
-
Select Basic or Advanced to
set up access controls (shown under the User Access
Control pane) for the displayed column family, as needed.
Note that the page options displayed after selecting
Basic or Advanced differ.
These differences are explained below. See the JSON Table Data Access Control Permission
Options or Binary Table Data
Access Control Permission Options tables below for permission
descriptions.
NOTEBy default, all permissions are given to the user creating the table. You can use either the default permissions that are automatically displayed or proceed to define new permissions for this column family.To grant or block access to users, groups, and/or roles, from the:
- Basic settings, select the type — public, (OR) user, group, or
role — from the drop-down menu, specify the name of the user, group, or role, and select
one or more checkbox to grant permissions.To add Access Control Expression (ACE)s for another user, group, or role, click Add Another and repeat this step.TIPClick to create a copy of the associated access control setting. Click to remove the associated access control expression.
- Advanced settings, specify public (
p
) or user (u
), group (g
), and/or role (r
) who have or do not have the type of access using the following boolean expressions and subexpressions:!
— Negation operator.&
— AND operation.|
— OR operation.
()
, parentheses, for subexpressions.NOTEYou cannot specify user, group, or role individually if access is granted to all users (public).Alternatively, click associated with the type of access to use the Access Control Expression window to define access for public or users, group, and/or role. See Defining ACEs Using the Access Control Expression Builder for more information.
NOTEIf you switch from Basic to Advanced, the basic settings, if any, are carried over to the advanced settings. If you switch from Advanced to Basic, all the settings are lost because the subexpressions and AND (&
) and negation (!
) operations that are supported by advanced settings are not supported in the basic settings.Option Option Description Read Data Can do column reads. Reads require permission both at the column-family level and at the field level. This permission is inherited by fields within the column family. Write Data Can do column writes. Writes require permission both at the column-family level and at the field level. This permission is inherited by fields within the column family. Traverse Data Can pass over fields in JSON documents. For example, suppose that a JSON table contains documents of this general structure:
Suppose further that the user sjohnson has read permission on{ "_id" : "ID", "a" : { "b" : "value", "c" : "value" } }
a.b
, but not ona
. For sjohnson to reada.b
, the user needs the traverse permission ona
. The user can then pass over fielda
toa.b
. This permission is inherited by fields within the column family.Set Compression Can set or change the compression setting for the column family. Unmasked Data Check Unmask Data to direct the system to show all data for the table column family for this new table. Leaving the Unmask Data unchecked directs the system to hide table column data when using this security policy for the selected user type. Option Option Description Read Data Can do column reads. Reads require permission both at the column-family level and at the field level. This permission is inherited by fields within the column family. Write Data Can do column writes. Writes require permission both at the column-family level and at the field level. This permission is inherited by fields within the column family. Append Data Can do column appends. Column appends require permission both at the column-family level and at the column level. Set Version Can set or change the maximum and minimum number of versions of column values to keep. Set Compression Can set or change the compression setting for the column family. - Basic settings, select the type — public, (OR) user, group, or
role — from the drop-down menu, specify the name of the user, group, or role, and select
one or more checkbox to grant permissions.
- Click Add Column Family to add the column family to the table. The name of newly created column family appears in the All pane of the tables information page.
- Opt to add field permissions to the newly created column family.
Creating Column Families Using CLI or the REST API
About this task
-jsonpath
and
-force
:maprcli table cf create -path <path> -cfname <name_of_column_family> -jsonpath
<path> -force true
For
the full list of options, see the table cf create
command.-jsonpath
parameter specifies the path to the
column family. The path is in dotted notation. For example, suppose
the table contained JSON documents that were of this general
structure:
{
"_id" : "ID",
"a" :
{
"b" :
{
"c" : "value",
},
"e" : "value"
}
}
You want to create a column family at the field d
in the new path a.b.d
because you plan to store image
files in fields in that column family. By default, every time you try to create a non-default column family in a JSON table,
this command fails and returns a warning message that you should ensure there is no
existing data at the specified path. Set the -force
parameter to
true
if you want to override this warning mechanism and create a column
family.
maprcli table cf create -path <path> -cfname <name_of_column_family>
For
the full list of options for this command, see the table cf
create
command.The format of the value of the -path
parameter depends on whether you are
creating a table on a local cluster or a remote cluster.
Creating a Column Family for a Binary Table Using HBase Shell
About this task
After starting the HBase shell, run the alter
command. Type
help
to see a list of commands and their syntax.