Create_Index subroutine [Revelation On-Line Wiki]

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====== Create_Index subroutine    ======


 
==== Description ====
 
Creates a Btree, Cross Reference, or Relational index for a specified column in a table. The type of index you create dictates the calling syntax.
 
==== Syntax ====
 
equ BTREETYPE$ to 1
Create_Index(BTREETYPE$, //tablename//, //columnname//, //casemode//, //createmode//)

equ CROSSREFTYPE$ to 2
Create_Index(CROSSREFTYPE$, //tablename//, //columnname//, //casemode//, //createmode//, //delimiterlist//, //stoplist//)

equ RELATIONALTYPE$ to 3
Create_Index(RELATIONALTYPE$, //tablename//, //columnname//, //casemode//, //createmode//, //desttable//, //destcolumn//, //sortmode//)
 
==== Parameters ====
 
The Create_Index subroutine has the following parameters; the first five parameters are identical regardless of the type of index you create. Parameters that differ by index type are defined separately in the sections that follow.

^Parameter^Description^
|//indextype//|The value of this parameter specifies the type of index you create.\\ \\ __Value__ __Description__\\ 1 - Btree.\\ 2 - Cross Reference.\\ 3 - Relational.|
|//tablename//|The name of the table to index.|
|//columnname//|The name of the column to index.|
|//casemode//|The case sensitivity of the index.\\ __Value__ __Description__\\ 0 - Creates an index that is not case-sensitive. All values are converted to uppercase in the index.\\ 1 - Creates a case-sensitive index. No case conversion is applied. Uppercase values saved to the index are stored in uppercase, and lowercase values saved to the index are stored in lowercase.|
|//createmode//|Specifies whether to build the indexes immediately or process them at a later time.\\ \\ __Value__ __Description__\\ 0 - Build the index at a later time, using the Update_Index stored procedure.\\ 1 - Build the index immediately.|

 
==== See Also ====
 
[[cross_reference_indexes|Cross Reference indices]], [[relational_indexes|Relational indices]], Btree indices
 
==== Example ====
The following examples show how to create indexes, programmatically.

<code>
declare subroutine Create_Index
declare function Get_Status

/* Create a Btree index on the column PART_NAME in the table CAR_PARTS. Values in the index are not converted to uppercase. Indexes are not updated immediately. The system stored procedure Update_Index can be run at a later time to update the indexes. */

Create_Index("1", "CAR_PARTS", "PART_NAME", "1", "0")

if Get_Status(ErrCodes) then
  GoSub ErrorHandling
end

/* Creates a Cross Reference index on the column TYPE_DESC in the CAR_PART_TYPES table. All values in the index are converted to uppercase. The indexes are built immediately. Delimiter_list is a space and a value mark. The default stop_list is used and two additional words are added to the default list: PRICE and DESCRIPTION. */

DelimiterList = "SPACE":@fm:"VM"
StopList = "2":@fm:"PRICE":@vm:"DESCRIPTION"

Create_Index("2", "CAR_PART_TYPES", "TYPE_DESC", "0", "1",
             DelimiterList, StopList)

/* Creates a Relational index between the CAR_PARTS table and the ORDER_INFO table. Information in the indexes is converted to uppercase. The index is built immediately. The sort mode for the index is TOP. */

Create_Index("3", "CAR_PARTS", "ORDER_PLACE", "0", "1",
             "ORDER_INFO", "PARTS", "1")
</code>