[TOC] # ALTER DATABASE ## 描述 该语句用来修改 DataBase 的属性。 ## 格式 ~~~ alter_database_stmt: ALTER DATABASE [database_name] [SET] alter_specification_list; alter_specification_list: alter_specification [alter_specification ...] alter_specification: [DEFAULT] {CHARACTER SET | CHARSET} [=] charset_name | [DEFAULT] COLLATE [=] collation_name | REPLICA_NUM [=] int_num | PRIMARY_ZONE [=] zone_name | {READ ONLY | READ WRITE} | DEFAULT TABLEGROUP [=] {NULL | table_group_name} ~~~ ## 参数解释 <table data-tag="table" id="table-ysf-6zs-ag0" class="table"><colgroup width="240" span="1" data-tag="col" id="col-ekb-if2-kpr" colwidth="1*" colnum="1" colname="col1" style="width:50%" class="col"></colgroup><colgroup width="470" span="1" data-tag="col" id="col-mke-j6i-oa1" colwidth="1*" colnum="2" colname="col2" style="width:50%" class="col"></colgroup><thead id="thead-pa0-kuy-2tj" class="thead"><tr id="tr-n4o-5ol-7tp"><th id="td-bqv-8xc-yy3"><p id="p-8mb-z31-594"><b>参数</b></p></th><th id="td-nbw-8cc-kzk"><p id="p-51g-7as-o7x"><b>描述</b></p></th></tr></thead><tbody data-tag="tbody" id="tbody-kut-6mq-g7a" class="tbody"><tr data-tag="tr" id="tr-7p7-iao-8qi" class="tr"><td data-tag="td" id="td-3xp-zyc-rma" class="td"><p data-tag="p" id="p-z2n-ucg-xkx" class="p">database_name</p></td><td data-tag="td" id="td-zti-gzy-nab" class="td"><p data-tag="p" id="p-7yf-ibe-mte" class="p">指定要修改属性的数据库名称。如果不指定，会对当前默认数据库进行修改。</p></td></tr><tr data-tag="tr" id="tr-fmq-um2-xkt" class="tr"><td data-tag="td" id="td-cy5-hny-vzh" class="td"><p data-tag="p" id="p-ikh-4wm-f5j" class="p">CHARSET charset_name</p></td><td data-tag="td" id="td-t2r-n8m-3di" class="td"><p data-tag="p" id="p-cy7-5uj-60z" class="p">指定要修改的字符集。</p></td></tr><tr data-tag="tr" id="tr-1o5-vr6-nr5" class="tr"><td data-tag="td" id="td-bm3-ahw-1eq" class="td"><p data-tag="p" id="p-3cp-lly-kos" class="p">COLLATE collation_name</p></td><td data-tag="td" id="td-7mv-l5m-t3x" class="td"><p data-tag="p" id="p-8xn-zpp-bvb" class="p">指定校对规则。</p></td></tr><tr data-tag="tr" id="tr-9gv-vgd-n12" class="tr"><td data-tag="td" id="td-11s-pwy-o31" class="td"><p data-tag="p" id="p-ktq-ej3-0nl" class="p">REPLICA_NUM int_num</p></td><td data-tag="td" id="td-jxn-5vz-xlu" class="td"><p data-tag="p" id="p-tjb-1j1-j2n" class="p">指定副本数。</p></td></tr><tr data-tag="tr" id="tr-36v-hgw-th1" class="tr"><td data-tag="td" id="td-at8-bw5-qq3" class="td"><p id="p-gs4-ffq-hm3">PRIMARY_ZONE zone_name</p></td><td data-tag="td" id="td-ckf-kq0-883" class="td"><p data-tag="p" id="p-t1t-38p-595" class="p">指定主 Zone。</p></td></tr><tr data-tag="tr" id="tr-g30-6ta-rru" class="tr"><td data-tag="td" id="td-cul-in7-hbq" class="td"><p data-tag="p" id="p-rbj-0j8-o1z" class="p">READ ONLY | READ WRITE</p></td><td data-tag="td" id="td-quy-z2y-td6" class="td"><p data-tag="p" id="p-95v-d9d-66t" class="p">设置数据库级只读或读写属性。</p></td></tr><tr data-tag="tr" id="tr-av1-gco-wzv" class="tr"><td data-tag="td" id="td-a4u-vd3-p9g" class="td"><p data-tag="p" id="p-ki1-5xr-uwj" class="p">DEFAULT TABLEGROUP table_group_name</p></td><td data-tag="td" id="td-2w0-n9v-fxs" class="td"><p data-tag="p" id="p-b4q-1j3-zdm" class="p">设置数据库默认表组信息，NULL 表示取消数据库默认表组。</p></td></tr></tbody></table> ## 示例 * 修改数据库 test2 的字符集为 UTF8MB4，校对规则为 UTF8MB4\_BIN，且为读写属性。 ~~~ OceanBase(admin@test)>alter database test2 DEFAULT CHARACTER SET UTF8MB4; Query OK, 0 rows affected (0.03 sec) OceanBase(admin@test)>alter database test2 DEFAULT COLLATE UTF8MB4_BIN; Query OK, 0 rows affected (0.03 sec) OceanBase(admin@test)>alter database test2 READ WRITE; Query OK, 0 rows affected (0.02 sec) ~~~