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3 min readTo get the distinct keys from a JSON column in Oracle, you can use the JSON_TABLE function to convert the JSON data into rows and columns. Then, you can use the DISTINCT keyword to retrieve only the unique keys from the JSON column. By doing this, you can easily extract the distinct keys present in the JSON data stored in the Oracle database.[rating:53c0aa98-76b9-464d-9d7f-79965c5bfde8]What is the logic behind using distinct keys when querying a JSON column in Oracle.
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3 min readIn PL/SQL Oracle, it is not possible to return multiple values of different types from a function or procedure. However, you can achieve this by using a user-defined datatype, a record type, or by returning a collection (such as a nested table or a varray) that contains multiple values of different types.For example, you can create a record type that contains fields for each of the values you want to return, and then return an instance of this record type from your function or procedure.
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4 min readTo check existence in Oracle using a condition, you can use the EXISTS keyword in a SQL query. The EXISTS keyword is used to check if a subquery returns any rows. You can use it in combination with a WHERE clause to apply a condition for checking the existence of a record. The syntax for using EXISTS in Oracle is as follows:SELECT column1, column2 FROM table_name WHERE EXISTS (subquery);In the subquery, you can specify the condition based on which you want to check for the existence of records.
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4 min readTo close an opened cursor in Oracle, you can use the CLOSE statement followed by the cursor name. This statement tells Oracle to release the resources associated with the cursor and free up memory.It is important to close a cursor once you are done using it to avoid unnecessary memory usage and potential performance issues. Failure to close a cursor can result in increased memory consumption and slower database operations.
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5 min readAfter updating a value in Oracle, you can check the previous value by using the RETURNING clause in the SQL statement. This clause allows you to retrieve the old value of the column before it was updated. You can use this in combination with a SELECT statement to view the previous value after the update has been executed.
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6 min readIn Oracle PL/SQL, special characters can be used in string literals, comments, and identifiers. Special characters can be used to represent non-printable characters, escape sequences, or non-ASCII characters. To use special characters in string literals, you can enclose the string in single quotes and use escape sequences for special characters such as newline (\n), tab (\t), and backslash (\). In comments, special characters like the forward slash (/) and asterisk (*) should be escaped.
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5 min readTo read or convert a long raw data type in Oracle, you can use the DBMS_LOB package in PL/SQL. This package provides procedures and functions for working with large objects such as long raw data.You can use the DBMS_LOB functions to read the long raw data into a temporary LOB variable, and then convert it to a different data type such as a varchar2 or blob.To read a long raw data type, you can use the DBMS_LOB.
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4 min readIn Oracle, the REGEXP_LIKE() function can be used for concatenation by incorporating it into a SQL query. This function is typically used for pattern matching within strings, but it can also be used to filter and concatenate values in a specific format.To use REGEXP_LIKE() for concatenation in Oracle, you can include it within the SELECT statement along with the CONCAT() or the double pipe (||) operator to append values together.
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6 min readTo zoom in or out with wxPython, you can use the SetScale method of wx.GraphicsContext. You can create a GraphicsContext object using the CreateGraphicsContext method of a wx.Window object. Once you have the GraphicsContext, you can use its SetScale method to zoom in or out by specifying values for the x and y scales. For example, to zoom in on an object by a factor of 2, you can use context.SetScale(2, 2). Similarly, to zoom out by a factor of 0.5, you can use context.SetScale(0.5, 0.5).
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5 min readTo fetch records between two timestamps in Oracle, you can use the "BETWEEN" keyword along with the "TO_TIMESTAMP" function. You can specify the start and end timestamps in the query to retrieve records that fall within that time range.
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4 min readWhen choosing the size of a tablespace in Oracle, it is important to consider factors such as the amount of data that will be stored in the tablespace, the growth rate of the data, and the allocated budget for storage. It is recommended to allocate enough space to accommodate the current data as well as future growth, to prevent performance issues and the need for frequent resizing of the tablespace.