This chapter describes the basic building blocks of the OLAP expression syntax. It contains these topics:
The naming conventions for dimensional objects follow standard Oracle naming rules. All names are case-insensitive.
owner.{ cube | dimension | table }.{ measure | column | attribute }
Table 1-1 Naming Conventions for Dimensional Objects
| Convention | Quoted ID | Unquoted ID |
|---|---|---|
|
Initial Character |
Any character. |
Alphabetic character from the database character set. |
|
Other Characters |
All characters, punctuation marks, and spaces are permitted. Double quotation marks and nulls (\0) are not permitted. |
Alphanumeric characters from the database character set and underscore (_) are permitted. The dollar sign ($) and pound sign (#) are permitted but not recommended. Double quotation marks and nulls (\0) are not permitted. |
|
Reserved Words |
Permitted but not recommended. |
Not permitted. |
GLOBAL.UNITS_CUBE.SALES identifies the SALES measure in the Units Cube.
TIME.DIM_KEY and TIME.LEVEL_NAME identify columns in the Time views.
TIME.CALENDAR identifies the CALENDAR hierarchy in the Time dimension.
TIME.CALENDAR.CALENDAR_YEAR identifies the CALENDAR_YEAR level of the CALENDAR hierarchy in the Time dimension.
GLOBAL.UNITS_FACT.MONTH_ID identifies a foreign key column in the UNITS_FACT table.
TIME_DIM.CALENDAR_YEAR_DSC identifies a column in the TIME_DIM table.
Table 1-2 describes the data types that can be used for cubes and measures.
Table 1-2 Dimensional Data Types
| Data Type | Description |
|---|---|
|
|
A 64-bit floating number. A |
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A 32-bit floating number. A |
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A fixed length character string with a length of size characters or bytes. The size can range from 1 to 2000. |
|
|
A valid date in the range from January 1, 4712 BC to December 31, 9999 CE. It contains the datetime fields |
|
|
A decimal number with precision p and scale s represented as a |
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A subtype of |
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A whole number represented as a |
|
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A period of time in days, hours, minutes, and seconds. The day precision is the maximum number of digits in the |
|
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A period of time in years and months. The precision is the number of digits in the |
|
|
A fixed length character string with a length of size characters. The size can range from 1 character to 2000 bytes. The maximum number of characters depends on the national character set, which can require up to four bytes per character. |
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|
A decimal number with precision p and scale s. The precision can range from 1 to 38. The scale can range from -84 to 127. A |
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|
A variable length Unicode character string with a maximum length of size characters. The size can range from 1 character to 4000 bytes. The maximum number of characters depends on the national character set, which can require up to four bytes per character. |
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A valid date that contains the datetime fields |
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A valid date with the same description as
|
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A valid date that contains the datetime fields |
|
|
A variable length character string with a maximum length of size characters or bytes. The size can range from 1 to 4000. |
An operator manipulates data items and returns a result. Operators manipulate individual data items called operands or arguments. They are represented by special characters or by keywords. Syntactically, an operator appears before an operand, after an operand, or between two operands.
The OLAP Expression Syntax has these types of operators:
For conditional operators, go to "Conditions".
A binary operator operates on two operands.
Here are two simple examples using numeric literals for the operands.
7 * 2 is 14.
(8/2) + 1 is 5.
This example multiplies the values of the Sales measure by a numeric literal to create a calculated measure named Sales Budget.
UNITS_CUBE.SALES * 1.06
Table 1-5 Multiplication Operator Example
| Product | Level | Sales | Sales Budget |
|---|---|---|---|
|
Hardware |
CLASS |
124191336 |
131642816 |
|
Desktop PCs |
FAMILY |
74556528 |
79029919 |
|
Monitors |
FAMILY |
3972142 |
4210470 |
|
Memory |
FAMILY |
5619219 |
5956372 |
|
Modems/Fax |
FAMILY |
5575726 |
5910269 |
|
CD/DVD |
FAMILY |
16129497 |
17097267 |
|
Portable PCs |
FAMILY |
18338225 |
19438518 |
The next example creates a calculated measure named Profit by subtracting Cost from Sales.
UNITS_CUBE.SALES - UNITS_CUBE.COST
| Product | Level | Sales | Cost | Profit |
|---|---|---|---|---|
| Hardware | CLASS | 124191336 | 116058248 | 8133088 |
| Desktop PCs | FAMILY | 74556528 | 71937312 | 2619215 |
| Monitors | FAMILY | 3972142 | 3546195 | 425947 |
| Memory | FAMILY | 5619219 | 4962527 | 656692 |
| Modems/Fax | FAMILY | 5575726 | 5162879 | 412847 |
| CD/DVD | FAMILY | 16129497 | 12510832 | 3618664 |
| Portable PCs | FAMILY | 18338225 | 17938502 | 399723 |
The concatenation operator (||) combines text expressions.
'The date today is: ' || sysdate generates a text string such as The date today is: 23-AUG-06.
The next example concatenates the level name and dimension keys of the Product dimension to create an identifier.
PRODUCT.LEVEL_NAME || ' ' || PRODUCT.DIM_KEY
| Level | Dim Key | Identifier |
|---|---|---|
| CLASS | HRD | CLASS HRD |
| FAMILY | DTPC | FAMILY DTPC |
| FAMILY | MON | FAMILY MON |
| FAMILY | MEM | FAMILY MEM |
| FAMILY | MOD | FAMILY MOD |
| FAMILY | DISK | FAMILY DISK |
| FAMILY | LTPC | FAMILY LTPC |
A condition specifies a combination of one or more expressions and logical (Boolean) operators. The OLAP Expression Syntax has these types of conditions:
NUMBER (0=FALSE, 1=TRUE)
Comparison conditions compare one expression with another.
You can use these comparison operators:
Table 1-6 Simple Comparison Operators
| Operator | Description |
|---|---|
|
|
Greater than |
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Greater than or equal to |
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Less than |
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Less than or equal to |
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Equal to |
|
|
Not equal to |
A group comparison condition specifies a comparison with any or all members in a list or subquery.
You can use these comparison operators:
Table 1-7 Group Comparison Operators
| Operator | Description |
|---|---|
|
|
Greater than |
|
|
Greater than or equal to |
|
|
Less than |
|
|
Less than or equal to |
|
|
Equal to |
|
|
Not equal to |
|
|
Returns true if one or more values in the list match, or false if no values match. |
|
|
Returns true if all values in the list match, or false if one or more values do not match. |
expr
{ = | != | ^= | <> | > | < | >= | <= }
{ ANY | SOME | ALL }
({ expression_list | subquery })
The BETWEEN operator tests whether a value is in a specific range of values. It returns true if the value being tested is greater than or equal to a low value and less than or equal to a high value.
Conjunctions compare a single expression with two conditions.
| Operator | Description |
|---|---|
|
|
Returns true if both component conditions are true. Returns false if either is false. |
|
|
Returns true if either component condition is true. Returns false if both are false. |
The NOT operator reverses the meaning of a condition. It returns true if the condition is false. It returns false if the condition is true.
The IS operator tests for special conditions, such as nulls, infinity and values that are not numbers.
Table 1-9 Special Conditions Operators
| Operator | Description |
|---|---|
|
|
Returns true if the expression is infinite, or false otherwise. For mappings only. |
|
|
Returns true if the expression is not a number, or false otherwise. For mappings only. |
|
|
Returns true if the expression is null, or false otherwise. |
The pattern-matching conditions compare character data.
The LIKE operators specify a test involving pattern matching. Whereas the equality operator (=) exactly matches one character value to another, the LIKE operators can match patterns defined by special pattern-matching ("wildcard") characters.
You can choose from these LIKE operators:
Table 1-10 LIKE Pattern-Matching Operators
| Operator | Description |
|---|---|
|
|
Uses characters in the input character set. |
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|
Uses Unicode complete characters. It treats a Unicode supplementary character as two characters. |
|
|
Uses UCS2 code points. It treats a Unicode supplementary character as one character. |
|
|
Uses UCS4 code points. It treats a composite character as one character. |
char1 is a text expression for the search value.
char2 is a text expression for the pattern. The pattern can contain these wildcard characters:
An underscore (_) matches exactly one character (as opposed to one byte in a multibyte character set) in the value.
A percent sign (%) can match zero or more characters (as opposed to bytes in a multibyte character set) in the value. A '%' cannot match a null.
esc_char is a text expression, usually a literal, that is one character long. This escape character identifies an underscore or a percent sign in the pattern as literal characters instead of wildcard characters. You can also search for the escape character itself by repeating it. For example, if @ is the escape character, then you can use @% to search for % and @@ to search for @.
The OLAP Expression Syntax has three types of literal expressions: strings, numbers, and null. Other data types must be created using conversion functions such as TO_DATE.
The terms text literal, character literal, and string are used interchangeably. They are always enclosed in single quotes to distinguish them from object names.
CASE expressions let you use IF... THEN... ELSE logic in expressions.
In a simple case expression, CASE searches for the first WHEN... THEN pair for which expr equals comparison_expr, then it returns return_expr. If none of the WHEN... THEN pairs meet this condition, and an ELSE clause exists, then CASE returns else_expr. Otherwise, CASE returns null.
In a searched CASE expression, CASE searches from left to right until it finds an occurrence of condition that is true, and then returns return_expr. If no condition is found to be true, and an ELSE clause exists, CASE returns else_expr. Otherwise, CASE returns null.
CASE { simple_case_expression | searched_case_expression } [ ELSE else_expression ] END simple_case_expression::= expr WHEN comparison_expr THEN return_expr [ WHEN comparison_expr THEN return_expr ]... searched_case_expression::= WHEN condition THEN return_expr [ WHEN condition THEN return_expr ]...
expr is the base expression being tested.
comparison_expr is the expression against which expr is being tested. It must be the same basic data type (numeric or text) as expr.
condition is a conditional expression.
return_expr is the value returned when a match is found or the condition is true.
This statement returns Single Item or Value Pack depending on whether the PACKAGE attribute of the PRODUCT dimension is null or has a value:
CASE PRODUCT.PACKAGE WHEN NULL THEN 'Single Item' ELSE 'Value Pack'END
| Product | Package | Category |
|---|---|---|
| 1.44MB External 3.5" Diskette | Executive | Value Pack |
| 1GB USB Drive | -- | Single Item |
| 512MB USB Drive | -- | Single Item |
| 56Kbps V.90 Type II Modem | Executive | Value Pack |
| 56Kbps V.92 Type II Fax/Modem | Laptop Value Pack | Value Pack |
| Deluxe Mouse | Executive | Value Pack |
| Envoy Ambassador | -- | Single Item |
| Envoy Executive | Executive | Value Pack |
| Envoy External Keyboard | Executive | Value Pack |
| Envoy Standard Laptop | Value Pack | Value Pack |
| External - DVD-RW - 8X | Executive | Value Pack |
| External 101-key keyboard | Multimedia | Value Pack |
| External 48X CD-ROM | -- | Single Item |
| Internal - DVD-RW - 6X | Multimedia | Value Pack |
The next statement increases the unit price by 20%, truncated to the nearest dollar, if the difference between price and cost is less than 10%. Otherwise, it returns the current unit price.
CASE WHEN PRICE_CUBE.UNIT_PRICE < PRICE_CUBE.UNIT_COST * 1.1 THEN TRUNC(PRICE_CUBE.UNIT_COST * 1.2) ELSE PRICE_CUBE.UNIT_PRICE END
| Product | Cost | Old Price |
|---|---|---|
| 1GB USB Drive | 483.55 | 546.83 |
| 512MB USB Drive | 234.69 | 275.91 |
| 56Kbps V.90 Type II Modem | 135.72 | 158.58 |
| 56Kbps V.92 Type II Fax/Modem | 95.01 | 111.08 |
| Envoy Ambassador | 2686.01 | 2850.88 |
| Envoy Executive | 2799.80 | 2943.96 |
| Envoy Standard | 1933.82 | 1921.62 |
| External - DVD-RW - 8X | 263.83 | 300.34 |
| External 48X CD-ROM | 223.11 | 254.15 |
| Internal - DVD-RW - 6X | 134.46 | 160.18 |
| Internal 48X CD-ROM | 108.32 | 127.54 |
| Internal 48X CD-ROM USB | 46.00 | 68.54 |
| Monitor- 17"Super VGA | 228.53 | 269.70 |
| Monitor- 19"Super VGA | 445.04 | 504.84 |
| Sentinel Financial | 1685.72 | 1764.14 |
| Sentinel Multimedia | 1849.17 | 1932.54 |
| Sentinel Standard | 1572.98 | 1610.53 |
The next example creates a Sales Budget calculated measure by multiplying Sales from the previous year by 1.06 for a 6% increase. The detail levels of all dimensions are excluded from the calculation. The Budget is projected only using data from 2006 or later.
CASE
WHEN TIME.END_DATE >= TO_DATE('01-JAN-2006')
AND TIME.LEVEL_NAME IN ('CALENDAR_YEAR', 'CALENDAR_QUARTER')
AND PRODUCT.LEVEL_NAME != 'ITEM'
AND CUSTOMER.LEVEL_NAME IN ('TOTAL', 'REGION', 'WAREHOUSE')
THEN TRUNC(LAG(UNITS_CUBE.SALES, 1) OVER HIERARCHY
(TIME.CALENDAR BY ANCESTOR AT LEVEL TIME.CALENDAR.CALENDAR_YEAR
POSITION FROM BEGINNING) * 1.06)
ELSE NULL
END
| Product | Time | Sales |
|---|---|---|
| Hardware | Q1.05 | 28172590 |
| Hardware | Q2.05 | 34520379 |
| Hardware | Q3.05 | 29466573 |
| Hardware | Q4.05 | 32031795 |
| Hardware | Q1.06 | 32711891 |
| Hardware | Q2.06 | 33637473 |
| Hardware | Q3.06 | 29227635 |
| Hardware | Q4.06 | 31319881 |
| Hardware | Q1.07 | -- |
| Hardware | Q2.07 | -- |
| Hardware | Q3.07 | -- |
| Hardware | Q4.07 | -- |
Qualified data references (QDRs) limit a dimensional object to a single member in one or more dimensions for the duration of a query.
expression [ qualifier [ , qualifier]... ]
qualifier::=
dimension_id = member_expression
Note: The outside square brackets shown in bold are part of the syntax. In this case, they do not indicate an optional argument.
expression is a dimensional expression, typically the name of a measure.
dimension_id is a cube dimension of expression.
member_expression resolves to a single member of dimension_id.