History for zodb_data

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Table zodb_data

 <table border=1>
 <th>Name</th><th>Description</th><th>Storing</th><th>Db field type</th>
 <tr>
  <td>z_oid</td>
  <td>OID</td>
  <td>binascii.b2a_base64 repr of oid</td>
  <td>CHAR(12) NOT NULL</td>
 </tr>
 <tr>
  <td>z_serial</td>
  <td>Serial number</td>
  <td>binascii.b2a_base64 repr of serial</td>
  <td>CHAR(12) NOT NULL</td>
 </tr>
 <tr>
  <td>z_pre</td>
  <td>Previous serial number</td>
  <td>binascii.b2a_base64 repr of prev serial for oid</td>
  <td>CHAR(12) DEFAULT '' NOT NULL</td>
 </tr>
 <tr>
   <td>z_status</td>
   <td>Status code</td>
   <td>Single char status code used for indicating record status (current, historical, ghost)</td>
   <td>CHAR(1) DEFAULT '' NOT NULL</td>
 </tr>
 <tr>
   <td>z_data</td>
   <td>Pickle data</td>
   <td>Arbitrary-length string</td>
   <td>BLOB or LONG RAW</td>
 </tr>
 <tr>
   <td>z_datalen</td>
   <td>Integer length of pickle in bytes</td>
   <td>Integer length of pickle in bytes</td>
   <td>INTEGER DEFAULT 0 NOT NULL</td>
 </tr>
 <tr>
   <td>z_version</td>
   <td>Version name</td>
   <td>String - 252 characters because that's the most Interbase can index on</td>
   <td>VARCHAR(252) DEFAULT '' NOT NULL</td>
 </tr>
 <tr>
   <td>z_nv</td>
   <td>Nonversion serial number</td>
   <td>binascii.b2a_base64 repr of serial</td>
   <td>CHAR(12) DEFAULT '' NOT NULL</td>
 </tr>
 <tr>
   <td>z_dataserial</td>
   <td>Serial number of record containing data for oid (used if data is null)</td>
   <td>binascii.b2a_base64 repr of a serial</td>
   <td>CHAR(12)</td>
 </tr>
</table>

Compound primary key:  (zoid, zserial)