Document SQLite function mappings

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bricelam · Oct 6, 2020 · 2be5f89 · 2be5f89
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diff --git a/entity-framework/core/providers/sqlite/functions.md b/entity-framework/core/providers/sqlite/functions.md
@@ -0,0 +1,103 @@
+---
+title: Function Mappings - SQLite Database Provider - EF Core
+description: Function Mappings of the SQLite EF Core database provider
+author: bricelam
+ms.date: 10/05/2020
+uid: core/providers/sqlite/built-in-functions
+---
+# Function Mappings of the SQLite EF Core Provider
+
+This table shows which .NET members are translated into which SQL functions when using the SQLite provider.
+
+## Binary functions
+
+.NET                  | SQL                             | Added in
+--------------------- | ------------------------------- | --------
+bytes.Contains(value) | instr(@bytes, char(@value)) > 0 | EF Core 5.0
+bytes.Length          | length(@bytes)                  | EF Core 5.0
+
+## Date and time functions
+
+.NET                            | SQL                                                                      | Added in
+------------------------------- | ------------------------------------------------------------------------ | --------
+DateTime.Now                    | datetime('now', 'localtime')
+DateTime.Today                  | datetime('now', 'localtime', 'start of day')
+DateTime.UtcNow                 | datetime('now')
+dateTime.AddDays(value)         | datetime(@dateTime, @value \|\| ' days')
+dateTime.AddHours(value)        | datetime(@dateTime, @d \|\| ' hours')
+dateTime.AddMilliseconds(value) | datetime(@dateTime, (@value / 1000.0) \|\| ' seconds')                   | EF Core 2.2
+dateTime.AddMinutes(value)      | datetime(@dateTime, @value \|\| ' minutes')
+dateTime.AddMonths(months)      | datetime(@dateTime, @months \|\| ' months')
+dateTime.AddSeconds(value)      | datetime(@dateTime, @value \|\| ' seconds')
+dateTime.AddTicks(value)        | datetime(@dateTime, (@value / 10000000.0) \|\| ' seconds')               | EF Core 2.2
+dateTime.AddYears(value)        | datetime(@dateTime, @value \|\| ' years')
+dateTime.Date                   | datetime(@dateTime, 'start of day')
+dateTime.Day                    | strftime('%d', @dateTime)
+dateTime.DayOfWeek              | strftime('%w', @dateTime)                                                | EF Core 2.2
+dateTime.DayOfYear              | strftime('%j', @dateTime)
+dateTime.Hour                   | strftime('%H', @dateTime)
+dateTime.Millisecond            | (strftime('%f', @dateTime) * 1000) % 1000
+dateTime.Minute                 | strftime('%M', @dateTime)
+dateTime.Month                  | strftime('%m', @dateTime)
+dateTime.Second                 | strftime('%S', @dateTime)
+dateTime.Ticks                  | (julianday(@dateTime) - julianday('0001-01-01 00:00:00')) * 864000000000 | EF Core 2.2
+dateTime.TimeOfDay              | time(@dateTime)                                                          | EF Core 3.0
+dateTime.Year                   | strftime('%Y', @dateTime)
+
+> [!NOTE]
+> Some SQL has been simplified for illustration purposes. The actual SQL is more complex to handle a wider range of values.
+
+## Numeric functions
+
+.NET                  | SQL                                  | Added in
+--------------------- | ------------------------------------ | --------
+-decimalValue         | ef_negate(@decimalValue)             | EF Core 5.0
+decimalValue - d      | ef_add(@decimalValue, ef_negate(@d)) | EF Core 5.0
+decimalValue * d      | ef_multiply(@decimalValue, @d)       | EF Core 5.0
+decimalValue / d      | ef_divide(@decimalValue, @d)         | EF Core 5.0
+decimalValue % d      | ef_mod(@decimalValue, @d)            | EF Core 5.0
+decimalValue + d      | ef_add(@decimalValue, @d)            | EF Core 5.0
+decimalValue < d      | ef_compare(@decimalValue, @d) < 0    | EF Core 5.0
+decimalValue <= d     | ef_compare(@decimalValue, @d) <= 0   | EF Core 5.0
+decimalValue > d      | ef_compare(@decimalValue, @d) > 0    | EF Core 5.0
+decimalValue >= d     | ef_compare(@decimalValue, @d) >= 0   | EF Core 5.0
+doubleValue % d       | ef_mod(@doubleValue, @d)             | EF Core 5.0
+floatValue % d        | ef_mod(@floatValue, @d)              | EF Core 5.0
+Math.Abs(value)       | abs(@value)
+Math.Max(val1, val2)  | max(@val1, @val2)
+Math.Min(val1, val2)  | min(@val1, @val2)
+Math.Round(d)         | round(@d)
+Math.Round(d, digits) | round(@d, @digits)
+
+> [!TIP]
+> SQL functions prefixed with *ef* are created by EF Core.
+
+## String functions
+
+.NET                                      | SQL                                            | Added in
+----------------------------------------- | ---------------------------------------------- | --------
+string.IsNullOrWhiteSpace(value)          | @value IS NULL OR trim(@value) = ''
+stringValue.Contains(value)               | instr(@stringValue, @value) > 0
+stringValue.EndsWith(value)               | @stringValue LIKE '%' \|\| @value
+stringValue.FirstOrDefault()              | substr(@stringValue, 1, 1)                     | EF Core 5.0
+stringValue.IndexOf(value)                | instr(@stringValue, @value) - 1
+stringValue.LastOrDefault()               | substr(@stringValue, length(@stringValue), 1)  | EF Core 5.0
+stringValue.Length                        | length(@stringValue)
+stringValue.Replace(oldValue, newValue)   | replace(@stringValue, @oldValue, @newValue)
+stringValue.StartsWith(value)             | @stringValue LIKE @value \|\| '%'
+stringValue.Substring(startIndex, length) | substr(@stringValue, @startIndex + 1, @length)
+stringValue.ToLower()                     | lower(@stringValue)
+stringValue.ToUpper()                     | upper(@stringValue)
+stringValue.Trim()                        | trim(@stringValue)
+stringValue.Trim(trimChar)                | trim(@stringValue, @trimChar)
+stringValue.TrimEnd()                     | rtrim(@stringValue)
+stringValue.TrimEnd(trimChar)             | rtrim(@stringValue, @trimChar)
+stringValue.TrimStart()                   | ltrim(@stringValue)
+stringValue.TrimStart(trimChar)           | ltrim(@stringValue, @trimChar)
+
+> [!NOTE]
+> Some SQL has been simplified for illustration purposes. The actual SQL is more complex to handle a wider range of values.
+
+## See also
+
+* [Spatial Function Mappings](xref:core/providers/sqlite/spatial#spatial-function-mappings)
diff --git a/entity-framework/core/providers/sqlite/spatial.md b/entity-framework/core/providers/sqlite/spatial.md
@@ -62,7 +62,7 @@ modelBuilder.Entity<City>().Property(c => c.Location)
     .HasColumnType("POINTZ");
 ```
 
-## Translated Operations
+## Spatial Function Mappings
 
 This table shows which [NetTopologySuite](https://nettopologysuite.github.io/NetTopologySuite/) (NTS) members are translated into which SQL functions.
 

diff --git a/entity-framework/toc.yml b/entity-framework/toc.yml
@@ -244,6 +244,8 @@
           href: core/providers/sqlite/index.md
         - name: SQLite limitations
           href: core/providers/sqlite/limitations.md
+        - name: Function Mappings
+          href: core/providers/sqlite/functions.md
         - name: Spatial data
           displayName: GIS
           href: core/providers/sqlite/spatial.md