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19 Απρ 2017 · I jotted down the following query which will list the index name and its columns for a particular table: select b.uniqueness, a.index_name, a.table_name, a.column_name from all_ind_columns a, all_indexes b where a.index_name=b.index_name and a.table_name = upper('table_name') order by a.table_name, a.index_name, a.column_position;
In this tutorial, you will learn how to use the Oracle CREATE INDEX statement to create a new index on one or more columns of a table.
10 Αυγ 2017 · Indexes. They're one of the most powerful and misunderstood aspects of SQL performance. In this post we'll look at the purpose of an index, how to create and choose choose your index type. Then finish with a discussion of how to decide what to index and how to see if it's useful.
You create an index on a nested table column by creating the index on the nested table storage table. Include the NESTED_TABLE_ID pseudocolumn of the storage table to create a UNIQUE index, which effectively ensures that the rows of a nested table value are distinct.
You can encapsulate application-specific index management routines as an indextype schema object, and then define a domain index on table columns or attributes of an object type. Extensible indexing can efficiently process application-specific operators.
Creating a new index – show you how to use the CREATE INDEX statement to create an index for one or more columns in a table. Removing an index – learn how to remove an existing index by using the DROP INDEX statement. Unique index – use unique indexes to enforce the uniqueness of values in the index column or columns.
An index creates an entry for each value that appears in the indexed columns. By default, Oracle creates B-tree indexes. Create an Index. Syntax. The syntax for creating an index in Oracle/PLSQL is: CREATE [UNIQUE] INDEX index_name. ON table_name (column1, column2, ... column_n) [ COMPUTE STATISTICS ]; UNIQUE.
