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10 sie 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.
- Storing Data as JSON Documents
So function-based indexes are fine if you know what you're...
- Query's Execution Plan
His job is to help you get the best out of the Oracle...
- Partitioning
12 Things Developers Will Love About Oracle Database 12c...
- 3 Indexes and Index-Organized Tables
Indexes are schema objects that can speed access to table...
- CREATE INDEX
Purpose. Use the CREATEINDEX statement to create an index...
- Storing Data as JSON Documents
Indexes are schema objects that can speed access to table rows. Index-organized tables are tables stored in an index structure. This chapter contains the following sections: Introduction to Indexes. Overview of B-Tree Indexes. Overview of Bitmap Indexes. Overview of Function-Based Indexes. Overview of Application Domain Indexes.
Purpose. Use the CREATEINDEX statement to create an index on: One or more columns of a table, a partitioned table, an index-organized table, or a cluster. One or more scalar typed object attributes of a table or a cluster. A nested table storage table for indexing a nested table column.
This Oracle tutorial explains how to create, rename and drop indexes in Oracle with syntax and examples. An index is a performance-tuning method of allowing faster retrieval of records.
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.
Indexes are optional structures, associated with tables and clusters, which allow SQL queries to execute more quickly. Just as the index in this guide helps you locate information faster than if there were no index, an Oracle Database index provides a faster access path to table data. You can use indexes without rewriting any queries.
If you have the privileges, you can use the ALL_INDEXES or USER_INDEXES views. The query would be: SELECT * FROM all_indexes WHERE table_name = 'COUNTRY'; If you want some information on the columns included in the index, you can select those from ALL_IND_COLUMNS.
