mysqlconf mysqlconf07

It’s not easy to do a DW in MySQL — but it’s not impossible either. Easier to go to Teradata than to write your own.

DW characteristics:

1) Organic, evolves over time from OLTP systems — issues, locking, large queries, # of userss.

2) Starts as a copy of OLTP, but changes over time — schema evolution, replication lag, duplicate data issues

3) Custom — designed from the ground up for DW — issues with getting it started, growth, aggregations, backup.

4) How do you update the data in the warehouse? — write/update/read/delete, write/read/delete, or write only — which means that roll out requires partitions or merge tables.

The secret to DW is partitioning — can be based on:
data — date, groups …

mysqlconf mysqlconf07

There are too many Japanese characters to be able to use one byte to handle all of them.

Hiragana — over 50 characters

Katakana — over 50 characters

Kanji — over 6,000 characters

So the Japanese Character set has to be multi-byte. JIS=Japan Industrial Standard, this specifies it.

JIS X 0208 in 1990, updated in 1997 — covers widely used characters, not all characters
JIS X 0213 in 2000, updated in 2004

There are also vendor defined Japanese charsets — NEC Kanji and IBM Kanji — these supplement JIS X 0208.

Cellphone specific symbols have been introduced, so the # of characters is actually increasing!

For JIS X 0208, there are multiple encodings — Shift_JIS (all characters are 2 …