Add replace keyword arg to SQLite.load! (#263)

Fixes #243. Allows changing the "load" generated statement from INSERT
to REPLACE. We also add in error checking on each statement execution,
otherwise we never see an error in the INSERT case for primary key
duplication (it just silently fails and doesn't insert, which isn't
great).

Author: quinnj

src/tables.jl

@@ -175,14 +175,15 @@ tableinfo(db::DB, name::AbstractString) =
     end
 
 """
-    source |> SQLite.load!(db::SQLite.DB, tablename::String; temp::Bool=false, ifnotexists::Bool=false, analyze::Bool=false)
-    SQLite.load!(source, db, tablename; temp=false, ifnotexists=false, analyze::Bool=false)
+    source |> SQLite.load!(db::SQLite.DB, tablename::String; temp::Bool=false, ifnotexists::Bool=false, replace::Bool=false, analyze::Bool=false)
+    SQLite.load!(source, db, tablename; temp=false, ifnotexists=false, replace::Bool=false, analyze::Bool=false)
 
 Load a Tables.jl input `source` into an SQLite table that will be named `tablename` (will be auto-generated if not specified).
 
-`temp=true` will create a temporary SQLite table that will be destroyed automatically when the database is closed
-`ifnotexists=false` will throw an error if `tablename` already exists in `db`
-`analyze=true` will execute `ANALYZE` at the end of the insert
+  * `temp=true` will create a temporary SQLite table that will be destroyed automatically when the database is closed
+  * `ifnotexists=false` will throw an error if `tablename` already exists in `db`
+  * `replace=false` controls whether an `INSERT INTO ...` statement is generated or a `REPLACE INTO ...`
+  * `analyze=true` will execute `ANALYZE` at the end of the insert
 """
 function load! end
 
@@ -222,7 +223,7 @@ function checknames(::Tables.Schema{names}, db_names::AbstractVector{String}) wh
 end
 
 function load!(sch::Tables.Schema, rows, db::DB, name::AbstractString, db_tableinfo::Union{NamedTuple, Nothing}, row=nothing, st=nothing;
-               temp::Bool=false, ifnotexists::Bool=false, analyze::Bool=false)
+               temp::Bool=false, ifnotexists::Bool=false, replace::Bool=false, analyze::Bool=false)
     # check for case-insensitive duplicate column names (sqlite doesn't allow)
     checkdupnames(sch.names)
     # check if `rows` column names match the existing table, or create the new one
@@ -234,7 +235,8 @@ function load!(sch::Tables.Schema, rows, db::DB, name::AbstractString, db_tablei
     # build insert statement
     columns = join(esc_id.(string.(sch.names)), ",")
     params = chop(repeat("?,", length(sch.names)))
-    stmt = _Stmt(db, "INSERT INTO $(esc_id(string(name))) ($columns) VALUES ($params)")
+    kind = replace ? "REPLACE" : "INSERT"
+    stmt = _Stmt(db, "$kind INTO $(esc_id(string(name))) ($columns) VALUES ($params)")
     # start a transaction for inserting rows
     transaction(db) do
         if row === nothing
@@ -246,8 +248,14 @@ function load!(sch::Tables.Schema, rows, db::DB, name::AbstractString, db_tablei
             Tables.eachcolumn(sch, row) do val, col, _
                 bind!(stmt, col, val)
             end
-            sqlite3_step(stmt.handle)
-            sqlite3_reset(stmt.handle)
+            r = sqlite3_step(stmt.handle)
+            if r == SQLITE_DONE
+                sqlite3_reset(stmt.handle)
+            elseif r != SQLITE_ROW
+                e = sqliteexception(db)
+                sqlite3_reset(stmt.handle)
+                throw(e)
+            end
             state = iterate(rows, st)
             state === nothing && break
             row, st = state

test/runtests.jl

@@ -526,7 +526,7 @@ end
 Tables.isrowtable(::Type{UnknownSchemaTable}) = true
 Tables.rows(x::UnknownSchemaTable) = x
 Base.length(x::UnknownSchemaTable) = 3
-Base.iterate(::UnknownSchemaTable, st=1) = st == 4 ? nothing : ((a=1, b=2, c=3), st + 1)
+Base.iterate(::UnknownSchemaTable, st=1) = st == 4 ? nothing : ((a=1, b=2 + st, c=3 + st), st + 1)
 
 @testset "misc" begin
 
@@ -536,15 +536,27 @@ SQLite.load!(UnknownSchemaTable(), db, "tbl")
 tbl = DBInterface.execute(db, "select * from tbl") |> columntable
 @test tbl == (
     a = [1, 1, 1],
-    b = [2, 2, 2],
-    c = [3, 3, 3]
+    b = [3, 4, 5],
+    c = [4, 5, 6]
 )
 
 # https://github.com/JuliaDatabases/SQLite.jl/issues/251
 q = DBInterface.execute(db, "select * from tbl")
 row, st = iterate(q)
-@test row.a == 1 && row.b == 2 && row.c == 3
+@test row.a == 1 && row.b == 3 && row.c == 4
 row2, st = iterate(q, st)
 @test_throws ArgumentError row.a
 
+# https://github.com/JuliaDatabases/SQLite.jl/issues/243
+db = SQLite.DB()
+DBInterface.execute(db, "create table tmp ( a INTEGER NOT NULL PRIMARY KEY, b INTEGER, c INTEGER )")
+@test_throws SQLite.SQLiteException SQLite.load!(UnknownSchemaTable(), db, "tmp")
+SQLite.load!(UnknownSchemaTable(), db, "tmp"; replace=true)
+tbl = DBInterface.execute(db, "select * from tmp") |> columntable
+@test tbl == (
+    a = [1],
+    b = [5],
+    c = [6]
+)
+
 end