source: main/trunk/greenstone2/perllib/DBDrivers/Readme.txt@ 30355

Last change on this file since 30355 was 30355, checked in by jmt12, 9 years ago

Initial checkin of OO drivers for new dbutils system

File size: 1.8 KB
Line 
1===== DBDriver =====
2
3Note that there are a couple of Drivers that could be further separated to
4have even better OO, but I started to get bogged down in multiple inheritence
5problems so I left them as is for now. For instance, separating PipedExecutable
6support from the 70HyphenFormat driver would increase flexibility, but then it
7becomes tricky to say which should inherit from which (in a single inheritence)
8or what order methods should be resolved (in multiple inheritence).
9
10Notes:
11* Didn't finish refactoring SQL based drivers
12* ServerDrivers refactoring not done.
13* Since TDBCluster was the only cluster, didn't do MergableDriver
14
15==== Inheritence Overview ====
16
17 * BaseDBDriver - superclass of all drivers. Some shared utility methods
18 including support for persistent connections (ala TDB).
19 Thus this is a candidate for separating out the the
20 PersistentConnectionsDriver.
21 * 70HyphenFormat - drivers that write and read their data via pipes to
22 external executables. Data is in simple Greenstone
23 archive form (i.e. key/value pairs and separated by
24 seventy hyphens) - this is a candidate for further
25 separating out a PipedExecutableDriver.
26 * GDBM - makes use of GDBM utils (txt2db, db2txt etc)
27 * GDBMTXTGZ - makes use of gzip (for later use with GDBM)
28 * JDBM - makes use of jdbm.jar and JDBMWrapper.jar
29 * TDB - makes use of TDB utils (txt2tdb, tdb2txt etc)
30 * SQLDrivers - drivers that read/write their data using SQL commands
31 * SQLITE - uses calls to SQLite3 via the command line
32 * MSSQL
33 * ServerDrivers - drivers that act as clients to externally running servers
34 * GDBMS - makes use of a custom GDBM server
35 * TDBS - makes use of a custom TDB server
36 * MergableDrivers - ???
37 * TDBC - ??? Knows how to merge several TDB files into one.
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