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5 min readThe "is" keyword in Oracle procedures is used as a delimiter to separate the parameters and the local variables within the procedure definition. It is not necessary for the functionality of the procedure, but helps in improving the readability and organization of the code. By using "is", developers can clearly distinguish between the parameters that are being passed into the procedure and the variables that are used within the procedure's body.
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4 min readTo remove '\r\n' from a base64 string in Oracle, you can use the REPLACE function to replace it with an empty string. Here is an example query that demonstrates how to do this: SELECT REPLACE(base64_string_column, '\r\n', '') AS cleaned_base64_string FROM your_table_name; In this query, 'base64_string_column' is the column in your table that contains the base64 string that you want to clean.
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3 min readTo update partial value in PostgreSQL, you can use the UPDATE statement with a WHERE clause to specify the condition for which rows to update. You can also use the SET clause to specify the columns and values that you want to update. By using a combination of WHERE and SET clauses, you can update only specific columns or values in a table, leaving the rest of the data unchanged. This allows you to update partial values in PostgreSQL without affecting the entire row.
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6 min readTo convert an outer join select query to a merge in Oracle, you can use the MERGE statement in Oracle to perform a similar operation. The MERGE statement allows you to merge data from a source table to a target table based on a specified condition.To convert the outer join select query to a merge statement, you would need to identify the source and target tables, specify the join condition, and define the actions to be taken when a match is found or not found.
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7 min readIn PostgreSQL, the bit data type is used to store fixed-length binary strings. When mapping a column with type bit(24) in PostgreSQL with Hibernate, you can use the @Type annotation along with the BitStringType class provided by Hibernate.To map a column with type bit(24), you can annotate the corresponding field in your entity class with @Column and @Type(type = "org.hibernate.type.BitStringType").
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5 min readTo count the number of files under a specific directory in Hadoop, you can use the Hadoop command line interface (CLI) or write a MapReduce program.Using the Hadoop CLI, you can run the following command: hadoop fs -count -q /path/to/directory This command will provide you with the count of files, directories, and bytes in the specified directory.Alternatively, you can write a MapReduce program to count the number of files in a directory.
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6 min readOne way to update data only when the data is changed in Oracle is by using a trigger. Triggers in Oracle are special kinds of stored procedures that are automatically executed or fired when certain events occur in a database.To implement this, you can create a trigger that is fired before an update operation on a particular table. Within the trigger, you can compare the old and new values of the data being updated. If the data has changed, then you can perform the update operation.
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4 min readTo read a Hadoop MapFile using Python, you can use the pyarrow library, which provides an interface for reading and writing MapFiles. First, you will need to install the pyarrow library using pip install pyarrow. Then, you can use the pyarrow.mapfile module to read the MapFile using the open function. You can then iterate over the records in the MapFile using the iter method of the MapFileReader object and access the key and value of each record using the key and value attributes.
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5 min readTo extract the timezone from a timestamp in PostgreSQL, you can use the AT TIME ZONE function along with the datetime value. This function converts the timestamp value to a specific timezone. For example, you can use the following query to extract the timezone from a timestamp:SELECT CURRENT_TIMESTAMP AT TIME ZONE 'UTC';This query will return the current timestamp in the UTC timezone.
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3 min readTo validate a BLOB object in Oracle, you can use various techniques such as checking the size of the BLOB, verifying if the BLOB contains valid data, and confirming that the BLOB is not null or empty. Additionally, you can also use PL/SQL code to validate the BLOB object by performing checks and comparisons with other data in the database. By implementing proper validation techniques, you can ensure the integrity and accuracy of the BLOB objects stored in Oracle databases.
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8 min readTo decrease the heartbeat time of slave nodes in Hadoop, you can adjust the dfs.heartbeat.interval and dfs.namenode.heartbeat.recheck-interval properties in the hdfs-site.xml configuration file. By decreasing these values, you can make the slave nodes report their status to the NameNode more frequently, resulting in a faster heartbeat time.