1.8/examples/constraints.md

Title: Apache Accumulo Constraints Example Notice: Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE file distributed with this work for additional information regarding copyright ownership. The ASF licenses this file to you under the Apache License, Version 2.0 (the “License”); you may not use this file except in compliance with the License. You may obtain a copy of the License at . http://www.apache.org/licenses/LICENSE-2.0 . Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an “AS IS” BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

This tutorial uses the following Java classes, which can be found in org.apache.accumulo.examples.simple.constraints in the examples-simple module:

AlphaNumKeyConstraint.java - a constraint that requires alphanumeric keys
NumericValueConstraint.java - a constraint that requires numeric string values

This an example of how to create a table with constraints. Below a table is created with two example constraints. One constraints does not allow non alpha numeric keys. The other constraint does not allow non numeric values. Two inserts that violate these constraints are attempted and denied. The scan at the end shows the inserts were not allowed.

$ ./bin/accumulo shell -u username -p password

Shell - Apache Accumulo Interactive Shell
-
- version: 1.5.0
- instance name: instance
- instance id: 00000000-0000-0000-0000-000000000000
-
- type 'help' for a list of available commands
-
username@instance> createtable testConstraints
username@instance testConstraints> constraint -a org.apache.accumulo.examples.simple.constraints.NumericValueConstraint
username@instance testConstraints> constraint -a org.apache.accumulo.examples.simple.constraints.AlphaNumKeyConstraint
username@instance testConstraints> insert r1 cf1 cq1 1111
username@instance testConstraints> insert r1 cf1 cq1 ABC
  Constraint Failures:
      ConstraintViolationSummary(constrainClass:org.apache.accumulo.examples.simple.constraints.NumericValueConstraint, violationCode:1, violationDescription:Value is not numeric, numberOfViolatingMutations:1)
username@instance testConstraints> insert r1! cf1 cq1 ABC
  Constraint Failures:
      ConstraintViolationSummary(constrainClass:org.apache.accumulo.examples.simple.constraints.NumericValueConstraint, violationCode:1, violationDescription:Value is not numeric, numberOfViolatingMutations:1)
      ConstraintViolationSummary(constrainClass:org.apache.accumulo.examples.simple.constraints.AlphaNumKeyConstraint, violationCode:1, violationDescription:Row was not alpha numeric, numberOfViolatingMutations:1)
username@instance testConstraints> scan
r1 cf1:cq1 []    1111
username@instance testConstraints>