Oracle does not index table rows in which all key columns are null except in the case of bitmap indexes. Therefore, if you want an index on all rows of a table, then you must either specifyNOTNULLconstraints for the index key columns or create a bitmap index. Restrictions on Bitmap I...
Oracle does not drop a nonunique index when the constraint is disabled, so subsequent ENABLE operations are facilitated.ENABLE VALIDATE specifies that all old and new data also complies with the constraint. An enabled validated constraint guarantees that all data is and will continue to be valid....
CREATE [UNIQUE | FULLTEXT | SPATIAL] INDEX index_name [index_type] ON tbl_name (key_part,...) [index_option] [algorithm_option | lock_option] ... key_part: {col_name [(length)] | (expr)} [ASC | DESC] index_option: { KEY_BLOCK_SIZE [=] value | index_type | WITH PARSER ...
CREATE INDEXSyntax CREATE [UNIQUE|FULLTEXT] INDEX index_name ON tbl_name (col_name[(length)],... ) TheCREATE INDEXstatement doesn’t do anything in MySQL prior to Version 3.22. In Version 3.22 or later,CREATE INDEXis mapped to anALTER TABLEstatement to create indexes. SeeSection 6.5.4....
oracle 租户下,创建数据库报错,create database xxx;ORA-00900: You have an error in your SQL syntax; check the manual that corresponds to your OceanBase version for the right syntax to use near 'xxx' at line 1 【 使用环境 】生产环境 or 测试环境...
The createIndex() method creates an index that you can define with a JSON document that specifies which fields to use. This section is a high level overview of indexing. For more information see Indexing Collections. Add a Nonunique Index To create a nonunique index, pass an index name and...
Specifies the DATE format for data import. This syntax is available only for READ ONLY foreign tables. Value range: any valid DATE value. For details, seeDate and Time Processing Functions and Operators. If ORACLE is specified as the compatible database, the DATE format is TIMESTAMP. For det...
syntaxsql CREATEDATABASESCOPEDCREDENTIALcredential_nameWITHIDENTITY='identity_name'[ ,SECRET='secret'] [ ; ] 参数 credential_name 指定创建的数据库范围凭据的名称。credential_name不能以数字 (#) 符号开头。 系统凭据从##. credential_name的最大长度为 128 个字符。
If you use the CREATE TABLE syntax to create an index on a partitioned table, the index will be created on each partition or subpartition. If the table definition includes the SUBPARTITION BY clause, each partition in the table will have a minimum of one subpartition. Each subpartition can ...
-- SQL Server Syntax CREATE [ UNIQUE ] [ CLUSTERED | NONCLUSTERED ] INDEX index_name ON ( column [ ASC | DESC ] [ ,...n ] ) [ INCLUDE ( column_name [ ,...n ] ) ] [ WHERE <filter_predicate> ] [ WITH ( <relational_index_option> [ ,...n ] ) ] [ ON {...