How to solve the problem of garbled characters when importing Chinese data into Oracle?

The retention period of Oracle database logs depends on the log type and configuration, including: Redo logs: determined by the maximum size configured with the "LOG_ARCHIVE_DEST" parameter. Archived redo logs: Determined by the maximum size configured by the "DB_RECOVERY_FILE_DEST_SIZE" parameter. Online redo logs: not archived, lost when the database is restarted, and the retention period is consistent with the instance running time. Audit log: Configured by the "AUDIT_TRAIL" parameter, retained for 30 days by default.

The Oracle database startup sequence is: 1. Check the preconditions; 2. Start the listener; 3. Start the database instance; 4. Wait for the database to open; 5. Connect to the database; 6. Verify the database status; 7. Enable the service (if necessary ); 8. Test the connection.

The amount of memory required by Oracle depends on database size, activity level, and required performance level: for storing data buffers, index buffers, executing SQL statements, and managing the data dictionary cache. The exact amount is affected by database size, activity level, and required performance level. Best practices include setting the appropriate SGA size, sizing SGA components, using AMM, and monitoring memory usage.

To find the number of occurrences of a character in Oracle, perform the following steps: Get the total length of a string; Get the length of the substring in which a character occurs; Count the number of occurrences of a character by subtracting the substring length from the total length.

Oracle database server hardware configuration requirements: Processor: multi-core, with a main frequency of at least 2.5 GHz. For large databases, 32 cores or more are recommended. Memory: At least 8GB for small databases, 16-64GB for medium sizes, up to 512GB or more for large databases or heavy workloads. Storage: SSD or NVMe disks, RAID arrays for redundancy and performance. Network: High-speed network (10GbE or higher), dedicated network card, low-latency network. Others: Stable power supply, redundant components, compatible operating system and software, heat dissipation and cooling system.

Oracle can read dbf files through the following steps: create an external table and reference the dbf file; query the external table to retrieve data; import the data into the Oracle table.

The amount of memory required for an Oracle database depends on the database size, workload type, and number of concurrent users. General recommendations: Small databases: 16-32 GB, Medium databases: 32-64 GB, Large databases: 64 GB or more. Other factors to consider include database version, memory optimization options, virtualization, and best practices (monitor memory usage, adjust allocations).

To create a scheduled task in Oracle that executes once a day, you need to perform the following three steps: Create a job. Add a subjob to the job and set its schedule expression to "INTERVAL 1 DAY". Enable the job.