Common index types and best practices shared in Oracle

Sharing common index types and best practices in Oracle

In Oracle database, index is one of the important mechanisms to improve query performance. Properly designing and using indexes can speed up queries and optimize database performance. This article will introduce the common index types in Oracle, as well as the best practices for using these indexes, and attach specific code examples.

1. Common index types

1. B-tree Index: The default index type, suitable for equality queries and range queries.
2. Unique Index: Ensure that the value of the index column is unique to avoid duplicate data.
3. Composite Index: Use multiple columns as index keys to improve the efficiency of multi-column queries.
4. Full-text Index: Used for full-text search on text data, supporting full-text search function.
5. Bitmap Index (Bitmap Index): It is suitable for high cardinality columns (column values ​​have few repetitions and is not suitable for range queries), and can effectively improve query performance.

2. Best practice sharing

1. Create indexes only for columns that are frequently used in query conditions, and avoid creating indexes for all columns to reduce index maintenance overhead. .
2. Avoid creating indexes on frequently updated columns because indexes will increase the complexity of update operations.
3. For range queries, try to place the range query column at the end of the index column in the composite index to obtain better performance.
4. Regularly analyze the usage of the index, and reorganize and rebuild the index according to the situation.
5. Use the appropriate index type to optimize the query, and select the appropriate index type according to the actual situation.

3. Code Example

The following is a simple example that demonstrates how to create a B-tree index and a unique index:

-- 创建表
CREATE TABLE employee (
    id NUMBER PRIMARY KEY,
    name VARCHAR2(50),
    department VARCHAR2(50)
);

-- 创建B树索引
CREATE INDEX idx_name ON employee(name);

-- 创建唯一索引
CREATE UNIQUE INDEX idx_id ON employee(id);

The above is common in Oracle Index types and best practices are shared. Properly designing and using indexes is an important means of optimizing database performance. I hope this article will be helpful to you.

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