Expression indexes can be used for computed columns

Author: mrotteveel

src/docs/asciidoc/en/refdocs/fblangref25/_fblangref25-ddl.adoc

@@ -2504,7 +2504,7 @@ The expression in a computed index may involve several columns in the table.
 
 [NOTE]
 ====
-You can actually create a computed index on a computed field, but the index will never be used.
+Expression indexes can also be used as a workaround for indexing computed columns: use the name of the computed column as the expression.
 ====
 
 [[fblangref25-ddl-idx-limits]]

src/docs/asciidoc/en/refdocs/fblangref25/_fblangref25-dochist.adoc

@@ -10,6 +10,12 @@ The exact file history is recorded in our _git_ repository; see https://github.c
 |===
 4+|Revision History
 
+|1.14
+|TBD
+|MR
+a|* Computed columns can be indexed with expression indexes
+* ...
+
 |1.13
 |26 May 2023
 |MR

src/docs/asciidoc/en/refdocs/fblangref25/firebird-25-language-reference.adoc

@@ -1,7 +1,7 @@
 [[fblangref25]]
 = Firebird 2.5 Language Reference
 Dmitry Filippov; Alexander Karpeykin; Alexey Kovyazin; Dmitry Kuzmenko; Denis Simonov; Paul Vinkenoog; Dmitry Yemanov
-1.13, 26 May 2023
+1.14, TBD 2023
 :doctype: book
 :sectnums:
 :sectanchors:

src/docs/asciidoc/en/refdocs/fblangref30/_fblangref30-dochist.adoc

@@ -10,6 +10,12 @@ The exact file history is recorded in our _git_ repository; see https://github.c
 |===
 4+|Revision History
 
+|1.16
+|TBD
+|MR
+a|* Computed columns can be indexed with expression indexes
+* ...
+
 |1.15
 |26 May 2023
 |MR

src/docs/asciidoc/en/refdocs/fblangref30/ddl/_fblangref30-ddl-index.adoc

@@ -113,7 +113,7 @@ The expression in a computed index may involve several columns in the table.
 
 [NOTE]
 ====
-You can actually create a computed index on a computed field, but such an index will never be used.
+Expression indexes can also be used as a workaround for indexing computed columns: use the name of the computed column as the expression.
 ====
 
 [[fblangref30-ddl-idx-limits]]

src/docs/asciidoc/en/refdocs/fblangref30/firebird-30-language-reference.adoc

@@ -1,7 +1,7 @@
 [[fblangref30]]
 = Firebird 3.0 Language Reference
 Dmitry Filippov; Alexander Karpeykin; Alexey Kovyazin; Dmitry Kuzmenko; Denis Simonov; Paul Vinkenoog; Dmitry Yemanov; Mark Rotteveel
-1.15, 26 May 2023
+1.16, TBD 2023
 :doctype: book
 :sectnums:
 :sectanchors:

src/docs/asciidoc/en/refdocs/fblangref40/_fblangref40-dochist.adoc

@@ -10,6 +10,12 @@ The exact file history is recorded in our _git_ repository; see https://github.c
 |===
 4+|Revision History
 
+|2.6
+|TBD
+|MR
+a|* Computed columns can be indexed with expression indexes
+* ...
+
 |2.5
 |26 May 2023
 |MR

src/docs/asciidoc/en/refdocs/fblangref40/ddl/_fblangref40-ddl-index.adoc

@@ -113,7 +113,7 @@ The expression in a computed index may involve several columns in the table.
 
 [NOTE]
 ====
-You can actually create a computed index on a computed field, but such an index will never be used.
+Expression indexes can also be used as a workaround for indexing computed columns: use the name of the computed column as the expression.
 ====
 
 [[fblangref40-ddl-idx-limits]]

src/docs/asciidoc/en/refdocs/fblangref40/firebird-40-language-reference.adoc

@@ -1,7 +1,7 @@
 [[fblangref40]]
 = Firebird 4.0 Language Reference
 Dmitry Filippov; Alexander Karpeykin; Alexey Kovyazin; Dmitry Kuzmenko; Denis Simonov; Paul Vinkenoog; Dmitry Yemanov; Mark Rotteveel
-2.5, 26 May 2023
+2.6, TBD 2023
 :doctype: book
 :sectnums:
 :sectanchors:

src/docs/asciidoc/en/refdocs/fblangref50/_fblangref50-dochist.adoc

@@ -10,6 +10,12 @@ The exact file history is recorded in our _git_ repository; see https://github.c
 |===
 4+|Revision History
 
+|0.4
+|TBD
+|MR
+a|* Computed columns can be indexed with expression indexes
+* ...
+
 |0.3
 |26 May 2023
 |MR

src/docs/asciidoc/en/refdocs/fblangref50/ddl/_fblangref50-ddl-index.adoc

@@ -39,7 +39,7 @@ The maximum length is 63 characters
 
 |col
 |Name of a column in the table.
-Columns of the types `BLOB` and `ARRAY` and computed fields cannot be used in an index
+Columns of the types `BLOB` and `ARRAY` and computed fields cannot be used in an index.
 
 |expression
 |The expression that will compute the values for a computed index, also known as an "`expression index`"
@@ -55,8 +55,7 @@ An index can be built on the content of columns of any data type except for `BLO
 The name (identifier) of an index must be unique among all index names.
 
 .Key Indexes
-[NOTE]
-====
+****
 When a primary key, foreign key or unique constraint is added to a table or column, an index with the same name is created automatically, without an explicit directive from the designer.
 For example, the `PK_COUNTRY` index will be created automatically when you execute and commit the following statement:
 
@@ -65,7 +64,7 @@ For example, the `PK_COUNTRY` index will be created automatically when you execu
 ALTER TABLE COUNTRY ADD CONSTRAINT PK_COUNTRY
   PRIMARY KEY (ID);
 ----
-====
+****
 
 [[fblangref50-ddl-idx-createidx-who]]
 === Who Can Create an Index?
@@ -133,7 +132,7 @@ The expression in a computed index may involve several columns in the table.
 
 [NOTE]
 ====
-You can create a computed index on a computed field, but such an index will never be used.
+Expression indexes can also be used as a workaround for indexing computed columns: use the name of the computed column as the expression.
 ====
 
 [[fblangref50-ddl-idx-limits]]

src/docs/asciidoc/en/refdocs/fblangref50/firebird-50-language-reference.adoc

@@ -1,7 +1,7 @@
 [[fblangref50]]
 = Firebird 5.0 Language Reference
 Dmitry Filippov; Alexander Karpeykin; Alexey Kovyazin; Dmitry Kuzmenko; Denis Simonov; Paul Vinkenoog; Dmitry Yemanov; Mark Rotteveel
-0.3, 26 May 2023
+0.4, TBD 2023
 :doctype: book
 :sectnums:
 :sectanchors: