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CHAPTER 11

Data Storage and Retrieval

Using Newton Data Storage Objects 11-45

following code fragment illustrates a query that returns entries having strings that

contain the substring

"Bob":

// find strings containing the substring "Bob"

local myCursor := mySoup:Query({text: "bob"});

This query ﬁnds entries containing words such as "JoeBob", as well as those

containing words such as

"bob" and "Bobby".

Internationalized Sorting Order for Text Queries 11

Indexes are not normally sensitive to case, diacritical marks, or ligatures in string

values; however, index and query speciﬁcations can request this behavior

speciﬁcally. When internationalized index ordering is used, uppercase letters sort

ﬁrst, followed by lowercase letters, diacritical marks, and ligatures. Thus, the letter

A sorts before the letter a, which sorts before the letter å, which sorts before the

letter

á, which sorts before the ligature æ.

To index string values in internationalized order, include an optional

sortID slot

holding the value

1 in the index speciﬁcation frame used to build a soup’s index. A

cursor subsequently generated against that soup returns entries holding the

following strings in the order listed here:

"AA", "aa", "åå", "EE", "ÉÉ", "ee"

This internationalized indexing order is available only for indexes on string values.

When the

sortID slot is missing from the index spec or this slot’s value is nil,

the index generated is not sensitive to case, diacritics, or ligatures; in other words,

the index may not necessarily sort

"AA" before "aa", and so on.

If an index has internationalized ordering, ﬁnd operations performed by cursors

generated against that index can be made sensitive to case and diacritics. To request

this behavior, include a non-

nil secOrder slot in the query spec passed to the

Query method of an internationally-indexed soup.

The value of the

secOrder slot affects the use of the beginKey, beginExclKey,

endKey, and endExclKey slots, as well as the GoToKey cursor method. For

example, sending the

GoToKey("åå") message to the cursor generated by this

query returns the ﬁrst entry found at or after the

"åå" index value but does not

return entries holding values that vary in case, diacritics, and so on.

When the

secOrder slot is missing or holds the value nil, ﬁnd operations

carried out by cursor methods such as

GoToKey ignore case and diacritics; that is,

they may return entries holding case and diacritic variations on the requested value.

For example, sending the

myCursor:GoToKey("åå") message returns the ﬁrst

entry found that holds any of the

"AA", "aa", or "åå" values. However, the

cursor generated by this query still uses the sorting order provided by the

1 2 ... 472 473 474 475 476 477 478 479 480 481 482 ... 941 942

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