Add PostgreSQL-specific character type constructors: Text, Char, and …

…VarChar.

README.md

@@ -175,9 +175,9 @@ stmt := SELECT(
         INNER_JOIN(FilmCategory, FilmCategory.FilmID.EQ(Film.FilmID)).
         INNER_JOIN(Category, Category.CategoryID.EQ(FilmCategory.CategoryID)),
 ).WHERE(
-    Language.Name.EQ(String("English")).             
-        AND(Category.Name.NOT_EQ(String("Action"))).  
-        AND(Film.Length.GT(Int(180))),               
+    Language.Name.EQ(Char(20)("English")).             
+        AND(Category.Name.NOT_EQ(Text("Action"))).  
+        AND(Film.Length.GT(Int32(180))),               
 ).ORDER_BY(
     Actor.ActorID.ASC(),
     Film.FilmID.ASC(),
@@ -200,35 +200,35 @@ args - query parameters
 
 ```sql
 SELECT actor.actor_id AS "actor.actor_id",
-     actor.first_name AS "actor.first_name",
-     actor.last_name AS "actor.last_name",
-     actor.last_update AS "actor.last_update",
-     film.film_id AS "film.film_id",
-     film.title AS "film.title",
-     film.description AS "film.description",
-     film.release_year AS "film.release_year",
-     film.language_id AS "film.language_id",
-     film.rental_duration AS "film.rental_duration",
-     film.rental_rate AS "film.rental_rate",
-     film.length AS "film.length",
-     film.replacement_cost AS "film.replacement_cost",
-     film.rating AS "film.rating",
-     film.last_update AS "film.last_update",
-     film.special_features AS "film.special_features",
-     film.fulltext AS "film.fulltext",
-     language.language_id AS "language.language_id",
-     language.name AS "language.name",
-     language.last_update AS "language.last_update",
-     category.category_id AS "category.category_id",
-     category.name AS "category.name",
-     category.last_update AS "category.last_update"
+       actor.first_name AS "actor.first_name",
+       actor.last_name AS "actor.last_name",
+       actor.last_update AS "actor.last_update",
+       film.film_id AS "film.film_id",
+       film.title AS "film.title",
+       film.description AS "film.description",
+       film.release_year AS "film.release_year",
+       film.language_id AS "film.language_id",
+       film.rental_duration AS "film.rental_duration",
+       film.rental_rate AS "film.rental_rate",
+       film.length AS "film.length",
+       film.replacement_cost AS "film.replacement_cost",
+       film.rating AS "film.rating",
+       film.last_update AS "film.last_update",
+       film.special_features AS "film.special_features",
+       film.fulltext AS "film.fulltext",
+       language.language_id AS "language.language_id",
+       language.name AS "language.name",
+       language.last_update AS "language.last_update",
+       category.category_id AS "category.category_id",
+       category.name AS "category.name",
+       category.last_update AS "category.last_update"
 FROM dvds.actor
-     INNER JOIN dvds.film_actor ON (actor.actor_id = film_actor.actor_id)
-     INNER JOIN dvds.film ON (film.film_id = film_actor.film_id)
-     INNER JOIN dvds.language ON (language.language_id = film.language_id)
-     INNER JOIN dvds.film_category ON (film_category.film_id = film.film_id)
-     INNER JOIN dvds.category ON (category.category_id = film_category.category_id)
-WHERE ((language.name = $1) AND (category.name != $2)) AND (film.length > $3)
+         INNER JOIN dvds.film_actor ON (actor.actor_id = film_actor.actor_id)
+         INNER JOIN dvds.film ON (film.film_id = film_actor.film_id)
+         INNER JOIN dvds.language ON (language.language_id = film.language_id)
+         INNER JOIN dvds.film_category ON (film_category.film_id = film.film_id)
+         INNER JOIN dvds.category ON (category.category_id = film_category.category_id)
+WHERE ((language.name = $1::char(20)) AND (category.name != $2::text)) AND (film.length > $3::integer)
 ORDER BY actor.actor_id ASC, film.film_id ASC;
 ```
 ```sh 
@@ -277,7 +277,7 @@ FROM dvds.actor
      INNER JOIN dvds.language ON (language.language_id = film.language_id)
      INNER JOIN dvds.film_category ON (film_category.film_id = film.film_id)
      INNER JOIN dvds.category ON (category.category_id = film_category.category_id)
-WHERE ((language.name = 'English') AND (category.name != 'Action')) AND (film.length > 180)
+WHERE ((language.name = 'English'::char(20)) AND (category.name != 'Action'::text)) AND (film.length > 180::integer)
 ORDER BY actor.actor_id ASC, film.film_id ASC;
 ```
 </details>
@@ -545,18 +545,18 @@ The most expensive bugs are the one discovered on the production, and the least
 With automatically generated type safe SQL, not only queries are written faster but bugs are found sooner.  
 Let's return to quick start example, and take closer look at a line:
  ```go
-AND(Film.Length.GT(Int(180))),
+AND(Film.Length.GT(Int32(180))),
 ```
 Let's say someone changes column `length` to `duration` from `film` table. The next go build will fail at that line, and 
 the bug will be caught at compile time.
 
-Let's say someone changes the type of `length` column to some non integer type. Build will also fail at the same line
+Let's say someone changes the type of `length` column to some non-integer type. Build will also fail at the same line
 because integer columns and expressions can be only compared to other integer columns and expressions.
 
 Build will also fail if someone removes `length` column from `film` table. `Film` field will be omitted from SQL Builder and Model types, 
 next time `jet` generator is run.
 
-Without Jet these bugs will have to be either caught by some test or by manual testing. 
+Without Jet these bugs will have to be either caught by tests or by manual testing. 
 
 ## Dependencies
 At the moment Jet dependence only of:

examples/quick-start/quick-start.go

@@ -46,8 +46,8 @@ func main() {
 			INNER_JOIN(FilmCategory, FilmCategory.FilmID.EQ(Film.FilmID)).
 			INNER_JOIN(Category, Category.CategoryID.EQ(FilmCategory.CategoryID)),
 	).WHERE(
-		Language.Name.EQ(String("English")).
-			AND(Category.Name.NOT_EQ(String("Action"))).
+		Language.Name.EQ(Char(20)("English")).
+			AND(Category.Name.NOT_EQ(Text("Action"))).
 			AND(Film.Length.GT(Int(180))),
 	).ORDER_BY(
 		Actor.ActorID.ASC(),

go.mod

@@ -1,19 +1,21 @@
 module github.com/go-jet/jet/v2
 
-go 1.20
+go 1.21
 
+// used by jet generator
 require (
 	github.com/go-sql-driver/mysql v1.8.1
-	github.com/google/go-cmp v0.6.0
 	github.com/google/uuid v1.6.0
 	github.com/jackc/pgconn v1.14.3
-	github.com/jackc/pgtype v1.14.3
+	github.com/jackc/pgtype v1.14.4
 	github.com/jackc/pgx/v4 v4.18.3
 	github.com/lib/pq v1.10.9
 	github.com/mattn/go-sqlite3 v1.14.24
 )
 
+// used in tests
 require (
+	github.com/google/go-cmp v0.6.0
 	github.com/pkg/profile v1.7.0
 	github.com/shopspring/decimal v1.4.0
 	github.com/stretchr/testify v1.9.0

go.sum

@@ -71,8 +71,8 @@ github.com/jackc/pgtype v0.0.0-20190824184912-ab885b375b90/go.mod h1:KcahbBH1nCM
 github.com/jackc/pgtype v0.0.0-20190828014616-a8802b16cc59/go.mod h1:MWlu30kVJrUS8lot6TQqcg7mtthZ9T0EoIBFiJcmcyw=
 github.com/jackc/pgtype v1.8.1-0.20210724151600-32e20a603178/go.mod h1:C516IlIV9NKqfsMCXTdChteoXmwgUceqaLfjg2e3NlM=
 github.com/jackc/pgtype v1.14.0/go.mod h1:LUMuVrfsFfdKGLw+AFFVv6KtHOFMwRgDDzBt76IqCA4=
-github.com/jackc/pgtype v1.14.3 h1:h6W9cPuHsRWQFTWUZMAKMgG5jSwQI0Zurzdvlx3Plus=
-github.com/jackc/pgtype v1.14.3/go.mod h1:aKeozOde08iifGosdJpz9MBZonJOUJxqNpPBcMJTlVA=
+github.com/jackc/pgtype v1.14.4 h1:fKuNiCumbKTAIxQwXfB/nsrnkEI6bPJrrSiMKgbJ2j8=
+github.com/jackc/pgtype v1.14.4/go.mod h1:aKeozOde08iifGosdJpz9MBZonJOUJxqNpPBcMJTlVA=
 github.com/jackc/pgx/v4 v4.0.0-20190420224344-cc3461e65d96/go.mod h1:mdxmSJJuR08CZQyj1PVQBHy9XOp5p8/SHH6a0psbY9Y=
 github.com/jackc/pgx/v4 v4.0.0-20190421002000-1b8f0016e912/go.mod h1:no/Y67Jkk/9WuGR0JG/JseM9irFbnEPbuWV2EELPNuM=
 github.com/jackc/pgx/v4 v4.0.0-pre1.0.20190824185557-6972a5742186/go.mod h1:X+GQnOEnf1dqHGpw7JmHqHc1NxDoalibchSk9/RWuDc=

postgres/literal.go

@@ -34,47 +34,64 @@ func Int64(value int64) IntegerExpression {
 	return CAST(jet.Int(value)).AS_BIGINT()
 }
 
-// Uint8 is constructor for 8 bit unsigned integer expressions literals.
-func Uint8(value uint8) IntegerExpression {
-	return CAST(jet.Uint8(value)).AS_SMALLINT()
-}
-
-// Uint16 is constructor for 16 bit unsigned integer expressions literals.
-func Uint16(value uint16) IntegerExpression {
-	return CAST(jet.Uint16(value)).AS_INTEGER()
-}
-
-// Uint32 is constructor for 32 bit unsigned integer expressions literals.
-func Uint32(value uint32) IntegerExpression {
-	return CAST(jet.Uint32(value)).AS_BIGINT()
-}
-
-// Uint64 is constructor for 64 bit unsigned integer expressions literals.
-func Uint64(value uint64) IntegerExpression {
-	return CAST(jet.Uint64(value)).AS_BIGINT()
-}
-
 // Float creates new float literal expression
 var Float = jet.Float
 
-// Float32 is constructor for 32 bit float literals
-func Float32(value float32) FloatExpression {
+// Real is placeholder constructor for 32-bit float literals
+func Real(value float32) FloatExpression {
 	return CAST(jet.Literal(value)).AS_REAL()
 }
 
-// Float64 is constructor for 64 bit float literals
-func Float64(value float64) FloatExpression {
+// Double is placeholder constructor for 64-bit float literals
+func Double(value float64) FloatExpression {
 	return CAST(jet.Literal(value)).AS_DOUBLE()
 }
 
 // Decimal creates new float literal expression
 var Decimal = jet.Decimal
 
-// String creates new string literal expression
+// String is a parameter constructor for the PostgreSQL text type. Using the `Text` constructor is
+// generally preferable.
+//
+// WARNING: String always applies a `text` type cast, which can be problematic if a parameter is compared
+// to a `character` column, as this may prevent index usage. In such cases, consider using the Char
+// constructor instead. See also other PostgreSQL-specific constructors: Text, Char, and VarChar.
 func String(value string) StringExpression {
 	return CAST(jet.String(value)).AS_TEXT()
 }
 
+// Text is a parameter constructor for the PostgreSQL text type. This constructor also adds an
+// explicit placeholder type cast to text in the generated query, such as `$3::text`.
+// Example usage:
+//
+//	Text("English")
+func Text(value string) StringExpression {
+	return CAST(jet.Literal(value)).AS_TEXT()
+}
+
+// Char is a parameter constructor for the PostgreSQL character type. This constructor also adds an
+// explicit placeholder type cast to text in the generated query, such as `$3::char(30)`.
+// Example usage:
+//
+//	Char(20)("English")
+func Char(length ...int) func(value string) StringExpression {
+	return func(value string) StringExpression {
+		return CAST(StringExp(jet.Literal(value))).AS_CHAR(length...)
+	}
+}
+
+// VarChar is a parameter constructor for the PostgreSQL character varying type. This constructor
+// also adds an explicit placeholder type cast to text in the generated query, such as `$3::varchar(30)`.
+// Example usage:
+//
+//	VarChar(20)("English")
+//	VarChar()("English")
+func VarChar(length ...int) func(value string) StringExpression {
+	return func(value string) StringExpression {
+		return CAST(StringExp(jet.Literal(value))).AS_VARCHAR(length...)
+	}
+}
+
 // Json creates new json literal expression
 func Json(value interface{}) StringExpression {
 	switch value.(type) {

postgres/literal_test.go

@@ -34,32 +34,21 @@ func TestInt64(t *testing.T) {
 	assertSerialize(t, Int64(val), `$1::bigint`, val)
 }
 
-func TestUint8(t *testing.T) {
-	val := uint8(math.MaxUint8)
-	assertSerialize(t, Uint8(val), `$1::smallint`, val)
-}
-
-func TestUint16(t *testing.T) {
-	val := uint16(math.MaxUint16)
-	assertSerialize(t, Uint16(val), `$1::integer`, val)
-}
-
-func TestUint32(t *testing.T) {
-	val := uint32(math.MaxUint32)
-	assertSerialize(t, Uint32(val), `$1::bigint`, val)
-}
-
-func TestUint64(t *testing.T) {
-	val := uint64(math.MaxUint64)
-	assertSerialize(t, Uint64(val), `$1::bigint`, val)
-}
-
 func TestFloat(t *testing.T) {
 	assertSerialize(t, Float(12.34), `$1`, float64(12.34))
+
+	assertSerialize(t, Real(12.34), `$1::real`, float32(12.34))
+	assertSerialize(t, Double(12.34), `$1::double precision`, float64(12.34))
 }
 
 func TestString(t *testing.T) {
 	assertSerialize(t, String("Some text"), `$1::text`, "Some text")
+
+	assertSerialize(t, Text("Some text"), `$1::text`, "Some text")
+	assertSerialize(t, Char(20)("John Doe"), `$1::char(20)`, "John Doe")
+	assertSerialize(t, Char()("John Doe"), `$1::char`, "John Doe")
+	assertSerialize(t, VarChar(20)("John Doe"), `$1::varchar(20)`, "John Doe")
+	assertSerialize(t, VarChar()("John Doe"), `$1::varchar`, "John Doe")
 }
 
 func TestBytea(t *testing.T) {

postgres/values.go

@@ -12,8 +12,8 @@ type values struct {
 // Example usage:
 //
 //	VALUES(
-//		WRAP(Int32(204), Float32(1.21)),
-//		WRAP(Int32(207), Float32(1.02)),
+//		WRAP(Int32(204), Real(1.21)),
+//		WRAP(Int32(207), Real(1.02)),
 //	)
 func VALUES(rows ...RowExpression) values {
 	return values{Values: jet.Values(rows)}

tests/postgres/alltypes_test.go

@@ -462,15 +462,15 @@ func TestStringOperators(t *testing.T) {
 
 	query := AllTypes.SELECT(
 		AllTypes.Text.EQ(AllTypes.Char),
-		AllTypes.Text.EQ(String("Text")),
+		AllTypes.Text.EQ(Text("Text")),
 		AllTypes.Text.NOT_EQ(AllTypes.VarCharPtr),
-		AllTypes.Text.NOT_EQ(String("Text")),
+		AllTypes.Text.NOT_EQ(Text("Text")),
 		AllTypes.Text.GT(AllTypes.Text),
-		AllTypes.Text.GT(String("Text")),
+		AllTypes.Text.GT(Text("Text")),
 		AllTypes.Text.GT_EQ(AllTypes.TextPtr),
-		AllTypes.Text.GT_EQ(String("Text")),
+		AllTypes.Text.GT_EQ(Text("Text")),
 		AllTypes.Text.LT(AllTypes.Char),
-		AllTypes.Text.LT(String("Text")),
+		AllTypes.Text.LT(Text("Text")),
 		AllTypes.Text.LT_EQ(AllTypes.VarChar),
 		AllTypes.Text.LT_EQ(String("Text")),
 		AllTypes.Text.BETWEEN(String("min"), String("max")),
@@ -490,13 +490,13 @@ func TestStringOperators(t *testing.T) {
 		OCTET_LENGTH(AllTypes.Text),
 		OCTET_LENGTH(String("length")),
 		LOWER(AllTypes.VarCharPtr),
-		LOWER(String("length")),
+		LOWER(Char(4)("length")),
 		UPPER(AllTypes.Char),
-		UPPER(String("upper")),
+		UPPER(VarChar()("upper")),
 		BTRIM(AllTypes.VarChar),
-		BTRIM(String("btrim")),
+		BTRIM(Char()("btrim")),
 		BTRIM(AllTypes.VarChar, String("AA")),
-		BTRIM(String("btrim"), String("AA")),
+		BTRIM(VarChar(11)("btrim"), String("AA")),
 		LTRIM(AllTypes.VarChar),
 		LTRIM(String("ltrim")),
 		LTRIM(AllTypes.VarChar, String("A")),
@@ -533,7 +533,7 @@ func TestStringOperators(t *testing.T) {
 		TO_HEX(AllTypes.IntegerPtr),
 	)
 
-	dest := []struct{}{}
+	var dest []struct{}
 	err := query.Query(db, &dest)
 
 	require.NoError(t, err)
@@ -630,9 +630,9 @@ func TestFloatOperators(t *testing.T) {
 		AllTypes.Numeric.BETWEEN(Float(1.34), AllTypes.Decimal).AS("between"),
 		AllTypes.Numeric.NOT_BETWEEN(AllTypes.Decimal.MUL(Float(3)), Float(100.12)).AS("not_between"),
 
-		TRUNC(AllTypes.Decimal.ADD(AllTypes.Decimal), Uint8(2)).AS("add1"),
+		TRUNC(AllTypes.Decimal.ADD(AllTypes.Decimal), Int8(2)).AS("add1"),
 		TRUNC(AllTypes.Decimal.ADD(Float(11.22)), Int8(2)).AS("add2"),
-		TRUNC(AllTypes.Decimal.SUB(AllTypes.DecimalPtr), Uint16(2)).AS("sub1"),
+		TRUNC(AllTypes.Decimal.SUB(AllTypes.DecimalPtr), Int32(2)).AS("sub1"),
 		TRUNC(AllTypes.Decimal.SUB(Float(11.22)), Int16(2)).AS("sub2"),
 		TRUNC(AllTypes.Decimal.MUL(AllTypes.DecimalPtr), Int16(2)).AS("mul1"),
 		TRUNC(AllTypes.Decimal.MUL(Float(11.22)), Int32(2)).AS("mul2"),
@@ -736,13 +736,13 @@ func TestIntegerOperators(t *testing.T) {
 		AllTypes.Integer.BETWEEN(Int(11), Int(200)).AS("between"),
 		AllTypes.Integer.NOT_BETWEEN(Int(66), Int(77)).AS("not_between"),
 		AllTypes.BigInt.LT(AllTypes.BigIntPtr).AS("lt1"),
-		AllTypes.BigInt.LT(Uint8(65)).AS("lt2"),
+		AllTypes.BigInt.LT(Int16(65)).AS("lt2"),
 		AllTypes.BigInt.LT_EQ(AllTypes.BigIntPtr).AS("lte1"),
-		AllTypes.BigInt.LT_EQ(Uint16(65)).AS("lte2"),
+		AllTypes.BigInt.LT_EQ(Int32(65)).AS("lte2"),
 		AllTypes.BigInt.GT(AllTypes.BigIntPtr).AS("gt1"),
-		AllTypes.BigInt.GT(Uint32(65)).AS("gt2"),
+		AllTypes.BigInt.GT(Int64(65)).AS("gt2"),
 		AllTypes.BigInt.GT_EQ(AllTypes.BigIntPtr).AS("gte1"),
-		AllTypes.BigInt.GT_EQ(Uint64(65)).AS("gte2"),
+		AllTypes.BigInt.GT_EQ(Int64(65)).AS("gte2"),
 
 		AllTypes.BigInt.ADD(AllTypes.BigInt).AS("add1"),
 		AllTypes.BigInt.ADD(Int(11)).AS("add2"),
@@ -1111,8 +1111,8 @@ func TestRowExpression(t *testing.T) {
 	nowAddHour := time.Now().Add(time.Hour)
 
 	stmt := SELECT(
-		ROW(Int32(1), Float32(11.22), String("john")).AS("row"),
-		WRAP(Int64(1), Float64(11.22), String("john")).AS("wrap"),
+		ROW(Int32(1), Real(11.22), Text("john")).AS("row"),
+		WRAP(Int64(1), Double(11.22), VarChar(10)("john")).AS("wrap"),
 
 		ROW(Bool(false), DateT(now)).EQ(ROW(Bool(true), DateT(now))),
 		WRAP(Bool(false), DateT(now)).NOT_EQ(WRAP(Bool(true), DateT(now))),
@@ -1131,7 +1131,7 @@ func TestRowExpression(t *testing.T) {
 
 	testutils.AssertStatementSql(t, stmt, `
 SELECT ROW($1::integer, $2::real, $3::text) AS "row",
-     ($4::bigint, $5::double precision, $6::text) AS "wrap",
+     ($4::bigint, $5::double precision, $6::varchar(10)) AS "wrap",
      ROW($7::boolean, $8::date) = ROW($9::boolean, $10::date),
      ($11::boolean, $12::date) != ($13::boolean, $14::date),
      ROW($15::time without time zone) IS DISTINCT FROM (row(NOW()::time)),