title: Multiple constraints on a single column
body: <p>I want to ensure that only the values 'Expert', 'Average' or 'Adequate' are entered into the <code>levelOfExpertise</code> column of this table, however whenever I do try an enter one of those values, it returns an error saying the value entered is too short. Here is the create table query for this particular table. The the column I am referring to is <code>levelOfExpertise</code>:</p>
  
  <pre><code>CREATE TABLE MusicianInstrument
  (
       musicianNo varchar(5) not null 
           CONSTRAINT MI_PK1 REFERENCES Musician(musicianNo),
       instrumentName varchar(50) not null 
           CONSTRAINT MI_PK2 REFERENCES Instrument(instrumentName),
       levelOfExpertise varchar(50),
  
       CONSTRAINT levelOfExpertise CHECK (levelOfExpertise = 'Expert', 'Adequate', 'Avergage'),
  
       PRIMARY KEY(musicianNo,instrumentName)
  );
  </code></pre>
  
  <p>Any ideas how I can ensure only those three values (<code>Expert</code>, <code>Adequate</code> or <code>Average</code>) can be entered?</p>
  
  <p>Thanks</p>