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22 Cards in this Set
- Front
- Back
- 3rd side (hint)
Check if a table exists in the current database schema... |
SELECT table_name FROM user_tables WHERE table_name = 'TABLE_NAME' |
Select statement |
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Check if a column exists in a table... |
SELECT column_name AS FOUND FROM user_tab_cols WHERE table_name = 'TABLE_NAME' AND column_name = 'COLUMN_NAME'; |
Select statement |
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Change current schema... |
ALTER SESSION SET CURRENT_SCHEMA = new_schema; |
Alter statement |
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Statement to return Oracle database version |
SELECT * FROM v$version; |
Select statement |
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Evaluate the following query: SELECT TRUNC(ROUND(156.00,-1),-1) FROM DUAL; |
160 |
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The first DROP operation is performed on PRODUCTS table using the following command: DROP TABLE products PURGE; Then you performed the FLASHBACK operation by using the following command: FLASHBACK TABLE products TO BEFORE DROP; Describe the outcome of the FLASHBACK statement... |
It is not possible to recover the table structure, data, or the related indexes. |
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True or False: Group functions can be used on columns or expressions |
True |
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True or False: Group functions can be passed as an argument to another function. |
True |
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True or False: Group functions can be used only with a SQL statement that has a GROUP BY clause. |
False |
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True or False: Group functions can be used on only one column in the SELECT clause of a SQL statement. |
False |
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True or False: Group functions can be used along with the single-row function in the SELECT clause of a SQL statement. |
True |
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True or False: The data dictionary is created and maintained by the database administrator. |
False |
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True or False: The data dictionary views consist of joins of dictionary base tables and user-defined tables |
False |
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True or False: The usernames of all the users including the database administrators are stored in the data dictionary. |
True |
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True or False: The USER_CONS_COLUMNS view should be queried to find the names of the columns to which a constraint applies |
True |
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True or False: both USER_OBJECTS and CAT views provide the same information about all the objects that are owned by the user. |
False |
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True or False: Views with the same name but different prefixes, such as DBA, ALL, and USER, use the same base tables from the data dictionary. |
True. |
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What are Group functions in Oracle? |
Group functions (a.k.a Aggregate functions) are built-in SQL functions that operate on groups of rows and return one value for the entire group. These functions include: COUNT, MAX, MIN, AVG, SUM, DISTINCT |
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Describe "Database Schema" |
A database schema is a collection of metadata that describes the relationship between the data in the database. A schema can be simply described as the "layout" of a database or the blueprint that outlines how data is organized into tables. |
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Describe "Schema Objects" |
Schema objects are database objects that contain data or that govern or perform operations on data. By definition, each schema object belongs to a specific schema. Common schema objects include: tables, indexes, and views. |
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True or False: Wildcard characters are only meaningful if the operator is LIKE or NOT LIKE |
True |
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True or False: Text cannot be combined with a column value using the concatenation operator unless single quotes surround the text. |
True |
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